Java/File Input Output/File Commands — различия между версиями
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Текущая версия на 06:02, 1 июня 2010
Содержание
- 1 BGrep: a regular expression search utility, like Unix grep
- 2 Compress files using the Java ZIP API
- 3 Copy files using Java IO API
- 4 Copying a file using channels and buffers
- 5 Count chars in a File
- 6 Counts words in a file, outputs results in sorted form
- 7 Delete a file from within Java, with error handling
- 8 Delete file using Java IO API
- 9 Diff: text file difference utility.
- 10 DirTree - directory lister, like UNIX ls or DOS and VMS dir
- 11 File concatenation
- 12 File Copy in Java
- 13 File Copy in Java with NIO
- 14 FNFilter - directory lister using FilenameFilter
- 15 Get file date and time
- 16 Grep tools
- 17 List root directory
- 18 Ls directory lister modified to use FilenameFilter
- 19 Mimic the Unix Grep command
- 20 mkdir examples
- 21 Move a File
- 22 Move File
- 23 Program to empty a directory
- 24 Program to remove files matching a name in a directory
- 25 Readonly Files
- 26 Rename a file in Java
- 27 Report on a file"s status in Java
- 28 Return readable file size with selected value measure
- 29 Simple directory lister
- 30 TeePrintStream tees all PrintStream operations into a file, rather like the UNIX tee(1) command
- 31 Touch: set File Last Modified Time
- 32 Undent - remove leading spaces
- 33 Word Count
BGrep: a regular expression search utility, like Unix grep
/*
* Copyright (c) 2004 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 3nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose,
* including teaching and use in open-source projects.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book,
* please visit http://www.davidflanagan.ru/javaexamples3.
*/
//package je3.nio;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;
/**
* BGrep: a regular expression search utility, like Unix grep, but
* block-oriented instead of line-oriented. For any match found, the filename
* and character position within the file (note: not the line number) are
* printed along with the text that matched.
*
* Usage: java je3.nio.BGrep [options] <pattern> <files>...
*
* Options: -e <encoding> specifies and encoding. UTF-8 is the default -i
* enables case-insensitive matching. Use -s also for non-ASCII text -s enables
* strict (but slower) processing of non-ASCII characters
*
* This program requires that each file to be searched fits into main memory,
* and so does not work with extremely large files.
*/
public class BGrep {
public static void main(String[] args) {
String encodingName = "UTF-8"; // Default to UTF-8 encoding
int flags = Pattern.MULTILINE; // Default regexp flags
try { // Fatal exceptions are handled after this try block
// First, process any options
int nextarg = 0;
while (args[nextarg].charAt(0) == "-") {
String option = args[nextarg++];
if (option.equals("-e")) {
encodingName = args[nextarg++];
} else if (option.equals("-i")) { // case-insensitive matching
flags |= Pattern.CASE_INSENSITIVE;
} else if (option.equals("-s")) { // Strict Unicode processing
flags |= Pattern.UNICODE_CASE; // case-insensitive Unicode
flags |= Pattern.CANON_EQ; // canonicalize Unicode
} else {
System.err.println("Unknown option: " + option);
usage();
}
}
// Get the Charset for converting bytes to chars
Charset charset = Charset.forName(encodingName);
// Next argument must be a regexp. Compile it to a Pattern object
Pattern pattern = Pattern.rupile(args[nextarg++], flags);
// Require that at least one file is specified
if (nextarg == args.length)
usage();
// Loop through each of the specified filenames
while (nextarg < args.length) {
String filename = args[nextarg++];
CharBuffer chars; // This will hold complete text of the file
try { // Handle per-file errors locally
// Open a FileChannel to the named file
FileInputStream stream = new FileInputStream(filename);
FileChannel f = stream.getChannel();
// Memory-map the file into one big ByteBuffer. This is
// easy but may be somewhat inefficient for short files.
ByteBuffer bytes = f.map(FileChannel.MapMode.READ_ONLY, 0, f.size());
// We can close the file once it is is mapped into memory.
// Closing the stream closes the channel, too.
stream.close();
// Decode the entire ByteBuffer into one big CharBuffer
chars = charset.decode(bytes);
} catch (IOException e) { // File not found or other problem
System.err.println(e); // Print error message
continue; // and move on to the next file
}
// This is the basic regexp loop for finding all matches in a
// CharSequence. Note that CharBuffer implements CharSequence.
// A Matcher holds state for a given Pattern and text.
Matcher matcher = pattern.matcher(chars);
while (matcher.find()) { // While there are more matches
// Print out details of the match
System.out.println(filename + ":" + // file name
matcher.start() + ": " + // character pos
matcher.group()); // matching text
}
}
}
// These are the things that can go wrong in the code above
catch (UnsupportedCharsetException e) { // Bad encoding name
System.err.println("Unknown encoding: " + encodingName);
} catch (PatternSyntaxException e) { // Bad pattern
System.err.println("Syntax error in search pattern:\n" + e.getMessage());
} catch (ArrayIndexOutOfBoundsException e) { // Wrong number of arguments
usage();
}
}
/** A utility method to display invocation syntax and exit. */
public static void usage() {
System.err.println("Usage: java BGrep [-e <encoding>] [-i] [-s]" + " <pattern> <filename>...");
System.exit(1);
}
}
Compress files using the Java ZIP API
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Compress {
public static void gzipFile(String from, String to) throws IOException {
FileInputStream in = new FileInputStream(from);
GZIPOutputStream out = new GZIPOutputStream(new FileOutputStream(to));
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = in.read(buffer)) != -1)
out.write(buffer, 0, bytesRead);
in.close();
out.close();
}
/** Zip the contents of the directory, and save it in the zipfile */
public static void zipDirectory(String dir, String zipfile)
throws IOException, IllegalArgumentException {
// Check that the directory is a directory, and get its contents
File d = new File(dir);
if (!d.isDirectory())
throw new IllegalArgumentException("Not a directory: "
+ dir);
String[] entries = d.list();
byte[] buffer = new byte[4096]; // Create a buffer for copying
int bytesRead;
ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipfile));
for (int i = 0; i < entries.length; i++) {
File f = new File(d, entries[i]);
if (f.isDirectory())
continue;//Ignore directory
FileInputStream in = new FileInputStream(f); // Stream to read file
ZipEntry entry = new ZipEntry(f.getPath()); // Make a ZipEntry
out.putNextEntry(entry); // Store entry
while ((bytesRead = in.read(buffer)) != -1)
out.write(buffer, 0, bytesRead);
in.close();
}
out.close();
}
public static void main(String args[]) throws IOException {
String from = ".";
File f = new File(from);
boolean directory = f.isDirectory(); // Is it a file or directory?
Compress.zipDirectory(from, from + ".zip");
Compress.gzipFile(from, from + ".gz");
}
}
Copy files using Java IO API
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
public class FileCopy {
public static void main(String[] args) {
try {
copy("fromFile.txt", "toFile.txt");
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
public static void copy(String fromFileName, String toFileName)
throws IOException {
File fromFile = new File(fromFileName);
File toFile = new File(toFileName);
if (!fromFile.exists())
throw new IOException("FileCopy: " + "no such source file: "
+ fromFileName);
if (!fromFile.isFile())
throw new IOException("FileCopy: " + "can"t copy directory: "
+ fromFileName);
if (!fromFile.canRead())
throw new IOException("FileCopy: " + "source file is unreadable: "
+ fromFileName);
if (toFile.isDirectory())
toFile = new File(toFile, fromFile.getName());
if (toFile.exists()) {
if (!toFile.canWrite())
throw new IOException("FileCopy: "
+ "destination file is unwriteable: " + toFileName);
System.out.print("Overwrite existing file " + toFile.getName()
+ "? (Y/N): ");
System.out.flush();
BufferedReader in = new BufferedReader(new InputStreamReader(
System.in));
String response = in.readLine();
if (!response.equals("Y") && !response.equals("y"))
throw new IOException("FileCopy: "
+ "existing file was not overwritten.");
} else {
String parent = toFile.getParent();
if (parent == null)
parent = System.getProperty("user.dir");
File dir = new File(parent);
if (!dir.exists())
throw new IOException("FileCopy: "
+ "destination directory doesn"t exist: " + parent);
if (dir.isFile())
throw new IOException("FileCopy: "
+ "destination is not a directory: " + parent);
if (!dir.canWrite())
throw new IOException("FileCopy: "
+ "destination directory is unwriteable: " + parent);
}
FileInputStream from = null;
FileOutputStream to = null;
try {
from = new FileInputStream(fromFile);
to = new FileOutputStream(toFile);
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = from.read(buffer)) != -1)
to.write(buffer, 0, bytesRead); // write
} finally {
if (from != null)
try {
from.close();
} catch (IOException e) {
;
}
if (to != null)
try {
to.close();
} catch (IOException e) {
;
}
}
}
}
Copying a file using channels and buffers
// : c12:ChannelCopy.java
// Copying a file using channels and buffers
// {Args: ChannelCopy.java test.txt}
// {Clean: test.txt}
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class ChannelCopy {
private static final int BSIZE = 1024;
public static void main(String[] args) throws Exception {
if (args.length != 2) {
System.out.println("arguments: sourcefile destfile");
System.exit(1);
}
FileChannel in = new FileInputStream(args[0]).getChannel(), out = new FileOutputStream(
args[1]).getChannel();
ByteBuffer buffer = ByteBuffer.allocate(BSIZE);
while (in.read(buffer) != -1) {
buffer.flip(); // Prepare for writing
out.write(buffer);
buffer.clear(); // Prepare for reading
}
}
} ///:~
Count chars in a File
/* From http://java.sun.ru/docs/books/tutorial/index.html */
/*
* Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* -Redistribution of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* -Redistribution in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
* AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
* EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed, licensed or intended
* for use in the design, construction, operation or maintenance of any
* nuclear facility.
*/
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class Count {
public static void countChars(InputStream in) throws IOException {
int count = 0;
while (in.read() != -1)
count++;
System.out.println("Counted " + count + " chars.");
}
public static void main(String[] args) throws Exception {
if (args.length >= 1)
countChars(new FileInputStream(args[0]));
else
System.err.println("Usage: Count filename");
}
}
Counts words in a file, outputs results in sorted form
// : c12:WordCount.java
// Counts words in a file, outputs results in sorted form.
// {Args: WordCount.java}
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeMap;
class Counter {
private int i = 1;
public int read() {
return i;
}
public void increment() {
i++;
}
}
public class WordCount1 {
private static final String usage = "Usage: \nWordCount file\n"
+ "Counts the words in the file and "
+ "outputs results in sorted form.";
private FileReader file;
private StreamTokenizer st;
// A TreeMap keeps keys in sorted order:
private TreeMap counts = new TreeMap();
public WordCount1(String filename) throws FileNotFoundException {
try {
file = new FileReader(filename);
st = new StreamTokenizer(new BufferedReader(file));
st.ordinaryChar(".");
st.ordinaryChar("-");
} catch (FileNotFoundException e) {
throw new RuntimeException(e);
}
}
public void dispose() {
try {
file.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public void countWords() {
try {
while (st.nextToken() != StreamTokenizer.TT_EOF) {
String s;
switch (st.ttype) {
case StreamTokenizer.TT_EOL:
s = new String("EOL");
break;
case StreamTokenizer.TT_NUMBER:
s = Double.toString(st.nval);
break;
case StreamTokenizer.TT_WORD:
s = st.sval; // Already a String
break;
default: // single character in ttype
s = String.valueOf((char) st.ttype);
}
if (counts.containsKey(s))
((Counter) counts.get(s)).increment();
else
counts.put(s, new Counter());
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public Collection values() {
return counts.values();
}
public Set keySet() {
return counts.keySet();
}
public Counter getCounter(String s) {
return (Counter) counts.get(s);
}
public static void main(String[] args) throws FileNotFoundException {
if (args.length == 0) {
System.out.println(usage);
System.exit(1);
}
WordCount1 wc = new WordCount1(args[0]);
wc.countWords();
Iterator keys = wc.keySet().iterator();
while (keys.hasNext()) {
String key = (String) keys.next();
System.out.println(key + ": " + wc.getCounter(key).read());
}
wc.dispose();
}
} ///:~
Delete a file from within Java, with error handling
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
/**
* Delete a file from within Java, with error handling.
*
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: Delete2.java,v 1.5 2004/02/09 03:33:47 ian Exp $
*/
public class Delete2 {
public static void main(String[] argv) {
for (int i = 0; i < argv.length; i++)
delete(argv[i]);
}
public static void delete(String fileName) {
try {
// Construct a File object for the file to be deleted.
File target = new File(fileName);
if (!target.exists()) {
System.err.println("File " + fileName
+ " not present to begin with!");
return;
}
// Quick, now, delete it immediately:
if (target.delete())
System.err.println("** Deleted " + fileName + " **");
else
System.err.println("Failed to delete " + fileName);
} catch (SecurityException e) {
System.err.println("Unable to delete " + fileName + "("
+ e.getMessage() + ")");
}
}
}
Delete file using Java IO API
import java.io.File;
public class Delete {
public static void main(String[] args) {
String fileName = "file.txt";
// A File object to represent the filename
File f = new File(fileName);
// Make sure the file or directory exists and isn"t write protected
if (!f.exists())
throw new IllegalArgumentException(
"Delete: no such file or directory: " + fileName);
if (!f.canWrite())
throw new IllegalArgumentException("Delete: write protected: "
+ fileName);
// If it is a directory, make sure it is empty
if (f.isDirectory()) {
String[] files = f.list();
if (files.length > 0)
throw new IllegalArgumentException(
"Delete: directory not empty: " + fileName);
}
// Attempt to delete it
boolean success = f.delete();
if (!success)
throw new IllegalArgumentException("Delete: deletion failed");
}
}
Diff: text file difference utility.
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
// Diff -- text file difference utility.
// See full docu-comment at beginning of Diff class.
// $Id: Diff.java,v 1.6 2004/02/09 03:34:05 ian Exp $
import java.io.*;
/** This is the info kept per-file. */
class fileInfo {
static final int MAXLINECOUNT = 20000;
DataInputStream file; /* File handle that is open for read. */
public int maxLine; /* After input done, # lines in file. */
node symbol[]; /* The symtab handle of each line. */
int other[]; /* Map of line# to line# in other file */
/* ( -1 means don"t-know ). */
/* Allocated AFTER the lines are read. */
/**
* Normal constructor with one filename; file is opened and saved.
*/
fileInfo( String filename ) {
symbol = new node [ MAXLINECOUNT+2 ];
other = null; // allocated later!
try {
file = new DataInputStream(
new FileInputStream( filename));
} catch (IOException e) {
System.err.println("Diff can"t read file " +
filename );
System.err.println("Error Exception was:" + e );
System.exit(1);
}
}
// This is done late, to be same size as # lines in input file.
void alloc() {
other = new int[symbol.length + 2];
}
};
/**
* diff Text file difference utility.
* ---- Copyright 1987, 1989 by Donald C. Lindsay,
* School of Computer Science, Carnegie Mellon University.
* Copyright 1982 by Symbionics.
* Use without fee is permitted when not for direct commercial
* advantage, and when credit to the source is given. Other uses
* require specific permission.
*
* Converted from C to Java by Ian F. Darwin, http://www.darwinsys.ru/, January, 1997.
* Copyright 1997, Ian F. Darwin.
*
* Conversion is NOT FULLY TESTED.
*
* USAGE: diff oldfile newfile
*
* This program assumes that "oldfile" and "newfile" are text files.
* The program writes to stdout a description of the changes which would
* transform "oldfile" into "newfile".
*
* The printout is in the form of commands, each followed by a block of
* text. The text is delimited by the commands, which are:
*
* DELETE AT n
* ..deleted lines
*
* INSERT BEFORE n
* ..inserted lines
*
* n MOVED TO BEFORE n
* ..moved lines
*
* n CHANGED FROM
* ..old lines
* CHANGED TO
* ..newer lines
*
* The line numbers all refer to the lines of the oldfile, as they are
* numbered before any commands are applied.
* The text lines are printed as-is, without indentation or prefixing. The
* commands are printed in upper case, with a prefix of ">>>>", so that
* they will stand out. Other schemes may be preferred.
* Files which contain more than MAXLINECOUNT lines cannot be processed.
* This can be fixed by changing "symbol" to a Vector.
* The algorithm is taken from Communications of the ACM, Apr78 (21, 4, 264-),
* "A Technique for Isolating Differences Between Files."
* Ignoring I/O, and ignoring the symbol table, it should take O(N) time.
* This implementation takes fixed space, plus O(U) space for the symbol
* table (where U is the number of unique lines). Methods exist to change
* the fixed space to O(N) space.
* Note that this is not the only interesting file-difference algorithm. In
* general, different algorithms draw different conclusions about the
* changes that have been made to the oldfile. This algorithm is sometimes
* "more right", particularly since it does not consider a block move to be
* an insertion and a (separate) deletion. However, on some files it will be
* "less right". This is a consequence of the fact that files may contain
* many identical lines (particularly if they are program source). Each
* algorithm resolves the ambiguity in its own way, and the resolution
* is never guaranteed to be "right". However, it is often excellent.
* This program is intended to be pedagogic. Specifically, this program was
* the basis of the Literate Programming column which appeared in the
* Communications of the ACM (CACM), in the June 1989 issue (32, 6,
* 740-755).
* By "pedagogic", I do not mean that the program is gracefully worded, or
* that it showcases language features or its algorithm. I also do not mean
* that it is highly accessible to beginners, or that it is intended to be
* read in full, or in a particular order. Rather, this program is an
* example of one professional"s style of keeping things organized and
* maintainable.
* The program would be better if the "print" variables were wrapped into
* a struct. In general, grouping related variables in this way improves
* documentation, and adds the ability to pass the group in argument lists.
* This program is a de-engineered version of a program which uses less
* memory and less time. The article points out that the "symbol" arrays
* can be implemented as arrays of pointers to arrays, with dynamic
* allocation of the subarrays. (In C, macros are very useful for hiding
* the two-level accesses.) In Java, a Vector would be used. This allows an
* extremely large value for MAXLINECOUNT, without dedicating fixed arrays.
* (The "other" array can be allocated after the input phase, when the exact
* sizes are known.) The only slow piece of code is the "strcmp" in the tree
* descent: it can be speeded up by keeping a hash in the tree node, and
* only using "strcmp" when two hashes happen to be equal.
*
* Change Log
* ----------
* 1Jan97 Ian F. Darwin: first working rewrite in Java, based entirely on
* D.C.Lindsay"s reasonable C version.
* Changed comments from /***************** to /**, shortened, added
* whitespace, used tabs more, etc.
* 6jul89 D.C.Lindsay, CMU: fixed portability bug. Thanks, Gregg Wonderly.
* Just changed "char ch" to "int ch".
* Also added comment about way to improve code.
* 10jun89 D.C.Lindsay, CMU: posted version created.
* Copyright notice changed to ACM style, and Dept. is now School.
* ACM article referenced in docn.
* 26sep87 D.C.Lindsay, CMU: publication version created.
* Condensed all 1982/83 change log entries.
* Removed all command line options, and supporting code. This
* simplified the input code (no case reduction etc). It also
* simplified the symbol table, which was capable of remembering
* offsets into files (instead of strings), and trusting (!) hash
* values to be unique.
* Removed dynamic allocation of arrays: now fixed static arrays.
* Removed speed optimizations in symtab package.
* Removed string compression/decompression code.
* Recoded to Unix standards from old Lattice/MSDOS standards.
* (This affected only the #include"s and the IO.)
* Some renaming of variables, and rewording of comments.
* 1982/83 D.C.Lindsay, Symbionics: created.
*
* @author Ian F. Darwin, Java version
* @version Java version 0.9, 1997
* @author D. C. Lindsay, C version (1982-1987)
*
*/
public class Diff {
/** block len > any possible real block len */
final int UNREAL=Integer.MAX_VALUE;
/** Keeps track of information about file1 and file2 */
fileInfo oldinfo, newinfo;
/** blocklen is the info about found blocks. It will be set to 0, except
* at the line#s where blocks start in the old file. At these places it
* will be set to the # of lines in the block. During printout ,
* this # will be reset to -1 if the block is printed as a MOVE block
* (because the printout phase will encounter the block twice, but
* must only print it once.)
* The array declarations are to MAXLINECOUNT+2 so that we can have two
* extra lines (pseudolines) at line# 0 and line# MAXLINECOUNT+1
* (or less).
*/
int blocklen[];
/**
* main - entry point when used standalone.
* NOTE: no routines return error codes or throw any local
* exceptions. Instead, any routine may complain
* to stderr and then exit with error to the system.
*/
public static void main(String argstrings[])
{
if ( argstrings.length != 2 ) {
System.err.println("Usage: diff oldfile newfile" );
System.exit(1);
}
Diff d = new Diff();
d.doDiff(argstrings[0], argstrings[1]);
return;
}
/** Construct a Diff object. */
Diff() {
}
/** Do one file comparison. Called with both filenames. */
public void doDiff(String oldFile, String newFile) {
println( ">>>> Difference of file \"" + oldFile +
"\" and file \"" + newFile + "\".\n");
oldinfo = new fileInfo(oldFile);
newinfo = new fileInfo(newFile);
/* we don"t process until we know both files really do exist. */
try {
inputscan( oldinfo );
inputscan( newinfo );
} catch (IOException e) {
System.err.println("Read error: " + e);
}
/* Now that we"ve read all the lines, allocate some arrays.
*/
blocklen = new int[ (oldinfo.maxLine>newinfo.maxLine?
oldinfo.maxLine : newinfo.maxLine) + 2 ];
oldinfo.alloc();
newinfo.alloc();
/* Now do the work, and print the results. */
transform();
printout();
}
/**
* inputscan Reads the file specified by pinfo.file.
* --------- Places the lines of that file in the symbol table.
* Sets pinfo.maxLine to the number of lines found.
*/
void inputscan( fileInfo pinfo ) throws IOException
{
String linebuffer;
pinfo.maxLine = 0;
while ((linebuffer = pinfo.file.readLine()) != null) {
storeline( linebuffer, pinfo );
}
}
/**
* storeline Places line into symbol table.
* --------- Expects pinfo.maxLine initted: increments.
* Places symbol table handle in pinfo.ymbol.
* Expects pinfo is either oldinfo or newinfo.
*/
void storeline( String linebuffer, fileInfo pinfo )
{
int linenum = ++pinfo.maxLine; /* note, no line zero */
if ( linenum > fileInfo.MAXLINECOUNT ) {
System.err.println( "MAXLINECOUNT exceeded, must stop." );
System.exit(1);
}
pinfo.symbol[ linenum ] =
node.addSymbol( linebuffer, pinfo == oldinfo, linenum );
}
/*
* transform
* Analyzes the file differences and leaves its findings in
* the global arrays oldinfo.other, newinfo.other, and blocklen.
* Expects both files in symtab.
* Expects valid "maxLine" and "symbol" in oldinfo and newinfo.
*/
void transform()
{
int oldline, newline;
int oldmax = oldinfo.maxLine + 2; /* Count pseudolines at */
int newmax = newinfo.maxLine + 2; /* ..front and rear of file */
for (oldline=0; oldline < oldmax; oldline++ )
oldinfo.other[oldline]= -1;
for (newline=0; newline < newmax; newline++ )
newinfo.other[newline]= -1;
scanunique(); /* scan for lines used once in both files */
scanafter(); /* scan past sure-matches for non-unique blocks */
scanbefore(); /* scan backwards from sure-matches */
scanblocks(); /* find the fronts and lengths of blocks */
}
/*
* scanunique
* Scans for lines which are used exactly once in each file.
* Expects both files in symtab, and oldinfo and newinfo valid.
* The appropriate "other" array entries are set to the line# in
* the other file.
* Claims pseudo-lines at 0 and XXXinfo.maxLine+1 are unique.
*/
void scanunique()
{
int oldline, newline;
node psymbol;
for( newline = 1; newline <= newinfo.maxLine; newline++ ) {
psymbol = newinfo.symbol[ newline ];
if ( psymbol.symbolIsUnique()) { // 1 use in each file
oldline = psymbol.linenum;
newinfo.other[ newline ] = oldline; // record 1-1 map
oldinfo.other[ oldline ] = newline;
}
}
newinfo.other[ 0 ] = 0;
oldinfo.other[ 0 ] = 0;
newinfo.other[ newinfo.maxLine + 1 ] = oldinfo.maxLine + 1;
oldinfo.other[ oldinfo.maxLine + 1 ] = newinfo.maxLine + 1;
}
/*
* scanafter
* Expects both files in symtab, and oldinfo and newinfo valid.
* Expects the "other" arrays contain positive #s to indicate
* lines that are unique in both files.
* For each such pair of places, scans past in each file.
* Contiguous groups of lines that match non-uniquely are
* taken to be good-enough matches, and so marked in "other".
* Assumes each other[0] is 0.
*/
void scanafter()
{
int oldline, newline;
for( newline = 0; newline <= newinfo.maxLine; newline++ ) {
oldline = newinfo.other[ newline ];
if ( oldline >= 0 ) { /* is unique in old & new */
for(;;) { /* scan after there in both files */
if ( ++oldline > oldinfo.maxLine ) break;
if ( oldinfo.other[ oldline ] >= 0 ) break;
if ( ++newline > newinfo.maxLine ) break;
if ( newinfo.other[ newline ] >= 0 ) break;
/* oldline & newline exist, and
aren"t already matched */
if ( newinfo.symbol[ newline ] !=
oldinfo.symbol[ oldline ] ) break; // not same
newinfo.other[newline] = oldline; // record a match
oldinfo.other[oldline] = newline;
}
}
}
}
/**
* scanbefore
* As scanafter, except scans towards file fronts.
* Assumes the off-end lines have been marked as a match.
*/
void scanbefore()
{
int oldline, newline;
for( newline = newinfo.maxLine + 1; newline > 0; newline-- ) {
oldline = newinfo.other[ newline ];
if ( oldline >= 0 ) { /* unique in each */
for(;;) {
if ( --oldline <= 0 ) break;
if ( oldinfo.other[ oldline ] >= 0 ) break;
if ( --newline <= 0 ) break;
if ( newinfo.other[ newline ] >= 0 ) break;
/* oldline and newline exist,
and aren"t marked yet */
if ( newinfo.symbol[ newline ] !=
oldinfo.symbol[ oldline ] ) break; // not same
newinfo.other[newline] = oldline; // record a match
oldinfo.other[oldline] = newline;
}
}
}
}
/**
* scanblocks - Finds the beginnings and lengths of blocks of matches.
* Sets the blocklen array (see definition).
* Expects oldinfo valid.
*/
void scanblocks()
{
int oldline, newline;
int oldfront = 0; // line# of front of a block in old, or 0
int newlast = -1; // newline"s value during prev. iteration
for( oldline = 1; oldline <= oldinfo.maxLine; oldline++ )
blocklen[ oldline ] = 0;
blocklen[ oldinfo.maxLine + 1 ] = UNREAL; // starts a mythical blk
for( oldline = 1; oldline <= oldinfo.maxLine; oldline++ ) {
newline = oldinfo.other[ oldline ];
if ( newline < 0 ) oldfront = 0; /* no match: not in block */
else{ /* match. */
if ( oldfront == 0 ) oldfront = oldline;
if ( newline != (newlast+1)) oldfront = oldline;
++blocklen[ oldfront ];
}
newlast = newline;
}
}
/* The following are global to printout"s subsidiary routines */
// enum{ idle, delete, insert, movenew, moveold,
// same, change } printstatus;
public static final int
idle = 0, delete = 1, insert = 2, movenew = 3, moveold = 4,
same = 5, change = 6;
int printstatus;
boolean anyprinted;
int printoldline, printnewline; // line numbers in old & new file
/**
* printout - Prints summary to stdout.
* Expects all data structures have been filled out.
*/
void printout()
{
printstatus = idle;
anyprinted = false;
for( printoldline = printnewline = 1; ; ) {
if ( printoldline > oldinfo.maxLine ) { newconsume(); break;}
if ( printnewline > newinfo.maxLine ) { oldconsume(); break;}
if ( newinfo.other[ printnewline ] < 0 ) {
if ( oldinfo.other[ printoldline ] < 0 )
showchange();
else
showinsert();
}
else if ( oldinfo.other[ printoldline ] < 0 )
showdelete();
else if ( blocklen[ printoldline ] < 0 )
skipold();
else if ( oldinfo.other[ printoldline ] == printnewline )
showsame();
else
showmove();
}
if ( anyprinted == true ) println( ">>>> End of differences." );
else println( ">>>> Files are identical." );
}
/*
* newconsume Part of printout. Have run out of old file.
* Print the rest of the new file, as inserts and/or moves.
*/
void newconsume()
{
for(;;) {
if ( printnewline > newinfo.maxLine )
break; /* end of file */
if ( newinfo.other[ printnewline ] < 0 ) showinsert();
else showmove();
}
}
/**
* oldconsume Part of printout. Have run out of new file.
* Process the rest of the old file, printing any
* parts which were deletes or moves.
*/
void oldconsume()
{
for(;;) {
if ( printoldline > oldinfo.maxLine )
break; /* end of file */
printnewline = oldinfo.other[ printoldline ];
if ( printnewline < 0 ) showdelete();
else if ( blocklen[ printoldline ] < 0 ) skipold();
else showmove();
}
}
/**
* showdelete Part of printout.
* Expects printoldline is at a deletion.
*/
void showdelete()
{
if ( printstatus != delete )
println( ">>>> DELETE AT " + printoldline);
printstatus = delete;
oldinfo.symbol[ printoldline ].showSymbol();
anyprinted = true;
printoldline++;
}
/*
* showinsert Part of printout.
* Expects printnewline is at an insertion.
*/
void showinsert()
{
if ( printstatus == change ) println( ">>>> CHANGED TO" );
else if ( printstatus != insert )
println( ">>>> INSERT BEFORE " + printoldline );
printstatus = insert;
newinfo.symbol[ printnewline ].showSymbol();
anyprinted = true;
printnewline++;
}
/**
* showchange Part of printout.
* Expects printnewline is an insertion.
* Expects printoldline is a deletion.
*/
void showchange()
{
if ( printstatus != change )
println( ">>>> " + printoldline + " CHANGED FROM");
printstatus = change;
oldinfo.symbol[ printoldline ].showSymbol();
anyprinted = true;
printoldline++;
}
/**
* skipold Part of printout.
* Expects printoldline at start of an old block that has
* already been announced as a move.
* Skips over the old block.
*/
void skipold()
{
printstatus = idle;
for(;;) {
if ( ++printoldline > oldinfo.maxLine )
break; /* end of file */
if ( oldinfo.other[ printoldline ] < 0 )
break; /* end of block */
if ( blocklen[ printoldline ]!=0)
break; /* start of another */
}
}
/**
* skipnew Part of printout.
* Expects printnewline is at start of a new block that has
* already been announced as a move.
* Skips over the new block.
*/
void skipnew()
{
int oldline;
printstatus = idle;
for(;;) {
if ( ++printnewline > newinfo.maxLine )
break; /* end of file */
oldline = newinfo.other[ printnewline ];
if ( oldline < 0 )
break; /* end of block */
if ( blocklen[ oldline ] != 0)
break; /* start of another */
}
}
/**
* showsame Part of printout.
* Expects printnewline and printoldline at start of
* two blocks that aren"t to be displayed.
*/
void showsame()
{
int count;
printstatus = idle;
if ( newinfo.other[ printnewline ] != printoldline ) {
System.err.println("BUG IN LINE REFERENCING");
System.exit(1);
}
count = blocklen[ printoldline ];
printoldline += count;
printnewline += count;
}
/**
* showmove Part of printout.
* Expects printoldline, printnewline at start of
* two different blocks ( a move was done).
*/
void showmove()
{
int oldblock = blocklen[ printoldline ];
int newother = newinfo.other[ printnewline ];
int newblock = blocklen[ newother ];
if ( newblock < 0 ) skipnew(); // already printed.
else if ( oldblock >= newblock ) { // assume new"s blk moved.
blocklen[newother] = -1; // stamp block as "printed".
println( ">>>> " + newother +
" THRU " + (newother + newblock - 1) +
" MOVED TO BEFORE " + printoldline );
for( ; newblock > 0; newblock--, printnewline++ )
newinfo.symbol[ printnewline ].showSymbol();
anyprinted = true;
printstatus = idle;
} else /* assume old"s block moved */
skipold(); /* target line# not known, display later */
}
/** Convenience wrapper for println */
public void println(String s) {
System.out.println(s);
}
}; // end of main class!
/**
* Class "node". The symbol table routines in this class all
* understand the symbol table format, which is a binary tree.
* The methods are: addSymbol, symbolIsUnique, showSymbol.
*/
class node{ /* the tree is made up of these nodes */
node pleft, pright;
int linenum;
static final int freshnode = 0,
oldonce = 1, newonce = 2, bothonce = 3, other = 4;
int /* enum linestates */ linestate;
String line;
static node panchor = null; /* symtab is a tree hung from this */
/**
* Construct a new symbol table node and fill in its fields.
* @param string A line of the text file
*/
node( String pline)
{
pleft = pright = null;
linestate = freshnode;
/* linenum field is not always valid */
line = pline;
}
/**
* matchsymbol Searches tree for a match to the line.
* @param String pline, a line of text
* If node"s linestate == freshnode, then created the node.
*/
static node matchsymbol( String pline )
{
int comparison;
node pnode = panchor;
if ( panchor == null ) return panchor = new node( pline);
for(;;) {
comparison = pnode.line.rupareTo(pline);
if ( comparison == 0 ) return pnode; /* found */
if ( comparison < 0 ) {
if ( pnode.pleft == null ) {
pnode.pleft = new node( pline);
return pnode.pleft;
}
pnode = pnode.pleft;
}
if ( comparison > 0 ) {
if ( pnode.pright == null ) {
pnode.pright = new node( pline);
return pnode.pright;
}
pnode = pnode.pright;
}
}
/* NOTE: There are return stmts, so control does not get here. */
}
/**
* addSymbol(String pline) - Saves line into the symbol table.
* Returns a handle to the symtab entry for that unique line.
* If inoldfile nonzero, then linenum is remembered.
*/
static node addSymbol( String pline, boolean inoldfile, int linenum )
{
node pnode;
pnode = matchsymbol( pline ); /* find the node in the tree */
if ( pnode.linestate == freshnode ) {
pnode.linestate = inoldfile ? oldonce : newonce;
} else {
if (( pnode.linestate == oldonce && !inoldfile ) ||
( pnode.linestate == newonce && inoldfile ))
pnode.linestate = bothonce;
else pnode.linestate = other;
}
if (inoldfile) pnode.linenum = linenum;
return pnode;
}
/**
* symbolIsUnique Arg is a ptr previously returned by addSymbol.
* -------------- Returns true if the line was added to the
* symbol table exactly once with inoldfile true,
* and exactly once with inoldfile false.
*/
boolean symbolIsUnique()
{
return (linestate == bothonce );
}
/**
* showSymbol Prints the line to stdout.
*/
void showSymbol()
{
System.out.println(line);
}
}
DirTree - directory lister, like UNIX ls or DOS and VMS dir
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
/**
* DirTree - directory lister, like UNIX ls or DOS and VMS dir
*
* @author Ian Darwin, http://www.darwinsys.ru/
* @version $Id: DirTree.java,v 1.4 2004/02/09 03:33:47 ian Exp $
*/
public class DirTree {
/** Main program */
public static void main(String[] argv) {
DirTree dt = new DirTree();
if (argv.length == 0)
dt.doDir(".");
else
for (int i = 0; i < argv.length; i++)
dt.doDir(argv[i]);
}
/** doDir - handle one filesystem object by name */
private void doDir(String s) {
File f = new File(s);
if (!f.exists()) {
System.out.println(s + " does not exist");
return;
}
if (f.isFile())
doFile(f);
else if (f.isDirectory()) {
System.out.println("d " + f.getPath());
String objects[] = f.list();
for (int i = 0; i < objects.length; i++)
doDir(s + f.separator + objects[i]);
} else
System.err.println("Unknown: " + s);
}
/** doFile - process one regular file. */
private static void doFile(File f) {
System.out.println("f " + f.getPath());
}
}
File concatenation
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
public class Cat {
public static void concatenate(String fileName) {
RandomAccessFile file = null;
String line = null;
try {
file = new RandomAccessFile(fileName, "r");
while ((line = file.readLine()) != null) {
System.out.println(line);
}
return;
} catch (FileNotFoundException fnf) {
System.err.println("File: " + fileName + " not found.");
} catch (Exception e) {
System.err.println(e.toString());
} finally {
if (file != null) {
try {
file.close();
} catch (IOException io) {
}
}
}
}
public static void main(String[] args) {
for (int i = 0; i < args.length; i++)
Cat.concatenate(args[i]);
}
}
File Copy in Java
/* From http://java.sun.ru/docs/books/tutorial/index.html */
/*
* Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* -Redistribution of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* -Redistribution in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
* AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
* EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed, licensed or intended
* for use in the design, construction, operation or maintenance of any
* nuclear facility.
*/
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class Copy {
public static void main(String[] args) throws IOException {
File inputFile = new File("farrago.txt");
File outputFile = new File("outagain.txt");
FileReader in = new FileReader(inputFile);
FileWriter out = new FileWriter(outputFile);
int c;
while ((c = in.read()) != -1)
out.write(c);
in.close();
out.close();
}
}
File Copy in Java with NIO
package com.jexp.tools.dev;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.channels.FileChannel;
class NioBenchmark1 {
static int size = 60; // MB
static int tests = 5;
interface Copier {
public void copy(File s, File t) throws IOException;
}
static class NioCopier implements Copier {
public void copy(File s, File t) throws IOException {
FileChannel in = (new FileInputStream(s)).getChannel();
FileChannel out = (new FileOutputStream(t)).getChannel();
in.transferTo(0, s.length(), out);
in.close();
out.close();
}
}
static class IoCopier implements Copier {
final int BUFF_SIZE = 5 * 1024 * 1024; // 5MB
final byte[] buffer = new byte[BUFF_SIZE];
public void copy(File s, File t) throws IOException {
InputStream in = new FileInputStream(s);
FileOutputStream out = new FileOutputStream(t);
while (true) {
int count = in.read(buffer);
if (count == -1)
break;
out.write(buffer, 0, count);
}
out.close();
in.close();
}
}
public static void main(String[] arg) throws IOException {
Copier io = new IoCopier();
Copier nio = new NioCopier();
nio.copy(new File("s"), new File("t"));
io.copy(new File("s"), new File("t"));
}
}
FNFilter - directory lister using FilenameFilter
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
import java.io.FilenameFilter;
/**
* FNFilter - directory lister using FilenameFilter
*
* @author Ian Darwin
*/
public class FNFilter2 implements FilenameFilter {
public static void main(String[] av) {
FNFilter2 ff = new FNFilter2();
ff.process(".");
}
public void process(String dir) {
String objects[] = (new File(dir)).list(this);
for (int i = 0; i < objects.length; i++)
System.out.println(objects[i]);
}
public boolean accept(File dir, String s) {
if (s.endsWith(".java"))
return true;
// others?
return false;
}
}
Get file date and time
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
/*
* IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
*
* http://izpack.org/
* http://izpack.codehaus.org/
*
* Copyright 2005 Marc Eppelmann
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* Provides general global file utility methods
*
* @author marc.eppelmann
*/
class FileUtil
{
//~ Constructors ***********************************************************************
/**
* Creates a new FileUtil object.
*/
public FileUtil()
{
}
//~ Methods ****************************************************************************
/**
* Gets the content from a File as StringArray List.
*
* @param fileName A file to read from.
* @return List of individual line of the specified file. List may be empty but not
* null.
* @throws IOException
*/
public static ArrayList getFileContent(String fileName)
throws IOException
{
ArrayList result = new ArrayList();
File aFile = new File(fileName);
if (!aFile.isFile())
{
//throw new IOException( fileName + " is not a regular File" );
return result; // None
}
BufferedReader reader = null;
try
{
reader = new BufferedReader(new FileReader(aFile));
}
catch (FileNotFoundException e1)
{
// TODO handle Exception
e1.printStackTrace();
return result;
}
String aLine = null;
while ((aLine = reader.readLine()) != null)
{
result.add(aLine + "\n");
}
reader.close();
return result;
}
/**
* Searches case sensitively, and returns true if the given SearchString occurs in the
* first File with the given Filename.
*
* @param aFileName A files name
* @param aSearchString the string search for
* @return true if found in the file otherwise false
*/
public static boolean fileContains(String aFileName, String aSearchString)
{
return (fileContains(aFileName, aSearchString, false));
}
/**
* Tests if the given File contains the given Search String
*
* @param aFileName A files name
* @param aSearchString the String to search for
* @param caseInSensitiveSearch If false the Search is casesensitive
* @return true if found in the file otherwise false
*/
public static boolean fileContains(String aFileName, String aSearchString,
boolean caseInSensitiveSearch)
{
boolean result = false;
String searchString = caseInSensitiveSearch
? aSearchString.toLowerCase() : aSearchString;
ArrayList fileContent = new ArrayList();
try
{
fileContent = getFileContent(aFileName);
}
catch (IOException e)
{
// TODO handle Exception
e.printStackTrace();
}
Iterator linesIter = fileContent.iterator();
while (linesIter.hasNext())
{
String currentline = (String) linesIter.next();
if (caseInSensitiveSearch)
{
currentline = currentline.toLowerCase();
}
if (currentline.indexOf(searchString) > -1)
{
result = true;
break;
}
}
return result;
}
/**
* Gets file date and time.
*
* @param url The URL of the file for which date and time will be returned.
* @return Returns long value which is the date and time of the file. If any error
* occures returns -1 (=no file date and time available).
*/
public static long getFileDateTime(URL url)
{
if (url == null)
{
return -1;
}
String fileName = url.getFile();
if (fileName.charAt(0) == "/" || fileName.charAt(0) == "\\")
{
fileName = fileName.substring(1, fileName.length());
}
try
{
File file = new File(fileName);
// File name must be a file or a directory.
if (!file.isDirectory() && !file.isFile())
{
return -1;
}
return file.lastModified();
}
catch (java.lang.Exception e)
{ // Trap all Exception based exceptions and return -1.
return -1;
}
}
public static String[] getFileNames(String dirPath) throws Exception
{
return getFileNames(dirPath, null);
}
public static String[] getFileNames(String dirPath, FilenameFilter fileNameFilter) throws Exception
{
String fileNames[] = null;
File dir = new File(dirPath);
if (dir.isDirectory())
{
if (fileNameFilter != null)
{
fileNames = dir.list(fileNameFilter);
}
else
{
fileNames = dir.list();
}
}
return fileNames;
}
/**
* Test main
*
* @param args
*/
public static void main(String[] args)
{
}
}
Grep tools
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Grep {
public static void main(String args[]) throws Exception {
String regex = "";
InputStream in = System.in;
regex = args[0];
in = new BufferedInputStream(new FileInputStream(args[1]));
Pattern p = null;
p = Pattern.rupile(regex);
BufferedReader buff = new BufferedReader(new InputStreamReader(in));
String a;
for (a = buff.readLine(); a != null; a = buff.readLine()) {
Matcher m = p.matcher(a);
if (m.find()) {
System.out.println(a);
}
}
}
}
List root directory
import java.io.File;
public class ListRoots {
public static void main(String argh_my_aching_fingers[]) {
File[] drives = File.listRoots(); // Get list of names
for (int i = 0; i < drives.length; i++)
System.out.println(drives[i]); // Print the list
}
}
Ls directory lister modified to use FilenameFilter
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
import java.io.FilenameFilter;
/**
* FNFilter - Ls directory lister modified to use FilenameFilter
*
* @author Ian Darwin
* @version $Id: FNFilter.java,v 1.3 2004/03/11 03:33:35 ian Exp $
*/
public class FNFilter {
public static void main(String argh_my_aching_fingers[]) {
// Generate the selective list, with a one-use File object.
String[] dir = new java.io.File(".").list(new OnlyJava());
java.util.Arrays.sort(dir); // Sort it (Data Structuring chapter))
for (int i = 0; i < dir.length; i++)
System.out.println(dir[i]); // Print the list
}
}
/**
* This class implements the FilenameFilter interface. The Accept method returns
* true for .java, .class and .jar files.
*/
class OnlyJava implements FilenameFilter {
public boolean accept(File dir, String s) {
if (s.endsWith(".java") || s.endsWith(".class") || s.endsWith(".jar"))
return true;
// others: projects, ... ?
return false;
}
}
Mimic the Unix Grep command
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
public class GrepReader extends BufferedReader {
String pattern;
public GrepReader(Reader in, String pattern) {
super(in);
this.pattern = pattern;
}
public final String readLine() throws IOException {
String line;
do {
line = super.readLine();
} while ((line != null) && line.indexOf(pattern) == -1);
return line;
}
public static void main(String args[]) {
try {
GrepReader in = new GrepReader(new FileReader("GrepReader.java"), "GrepReader");
String line;
while ((line = in.readLine()) != null)
System.out.println(line);
in.close();
} catch (Exception e) {
System.err.println(e);
}
}
}
mkdir examples
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
/**
* The collected mkdir examples (JavaCook 2e, Recipe 11.9).
*/
public class MkDirExamples {
public static void main(String[] args) {
boolean status;
status = new File("/home/ian/bin").mkdir();
report(status);
status = new File("/home/ian/src").mkdir();
report(status);
status = new File("/home/ian/once/twice/again").mkdir(); // should fail
report(status);
status = new File("/home/ian/once/twice/again").mkdirs(); // should
// succeed
report(status);
}
static void report(boolean b) {
System.out.println(b ? "success" : "failure");
}
}
Move a File
/*
* Static File routines.
* Copyright (C) 2002 Stephen Ostermiller
* http://ostermiller.org/contact.pl?regarding=Java+Utilities
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* See COPYING.TXT for details.
*/
import java.io.*;
import java.text.MessageFormat;
import java.util.ResourceBundle;
import java.util.Locale;
/**
* Utilities for File manipulation.
* More information about this class is available from .
*
* @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
* @since ostermillerutils 1.00.00
*/
public class FileHelper {
/**
* Locale specific strings displayed to the user.
*
* @since ostermillerutils 1.00.00
*/
protected static ResourceBundle labels = ResourceBundle.getBundle("com.Ostermiller.util.FileHelper", Locale.getDefault());
/**
* Move a file from one location to another. An attempt is made to rename
* the file and if that fails, the file is copied and the old file deleted.
*
* If the destination file already exists, an exception will be thrown.
*
* @param from file which should be moved.
* @param to desired destination of the file.
* @throws IOException if an error occurs.
*
* @since ostermillerutils 1.00.00
*/
public static void move(File from, File to) throws IOException {
move(from, to, false);
}
/**
* Move a file from one location to another. An attempt is made to rename
* the file and if that fails, the file is copied and the old file deleted.
*
* @param from file which should be moved.
* @param to desired destination of the file.
* @param overwrite If false, an exception will be thrown rather than overwrite a file.
* @throws IOException if an error occurs.
*
* @since ostermillerutils 1.00.00
*/
public static void move(File from, File to, boolean overwrite) throws IOException {
if (to.exists()){
if (overwrite){
if (!to.delete()){
throw new IOException(
MessageFormat.format(
labels.getString("deleteerror"),
(Object[])new String[] {
to.toString()
}
)
);
}
} else {
throw new IOException(
MessageFormat.format(
labels.getString("alreadyexistserror"),
(Object[])new String[] {
to.toString()
}
)
);
}
}
if (from.renameTo(to)) return;
InputStream in = null;
OutputStream out = null;
try {
in = new FileInputStream(from);
out = new FileOutputStream(to);
copy(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
if (!from.delete()){
throw new IOException(
MessageFormat.format(
labels.getString("deleteoriginalerror"),
(Object[])new String[] {
from.toString(),
to.toString()
}
)
);
}
} finally {
if (in != null){
in.close();
in = null;
}
if (out != null){
out.flush();
out.close();
out = null;
}
}
}
/**
* Buffer size when reading from input stream.
*
* @since ostermillerutils 1.00.00
*/
private final static int BUFFER_SIZE = 1024;
/**
* Copy the data from the input stream to the output stream.
*
* @param in data source
* @param out data destination
* @throws IOException in an input or output error occurs
*
* @since ostermillerutils 1.00.00
*/
private static void copy(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[BUFFER_SIZE];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}
}
Move File
/**
* Copyright (c) 2003 - 2007 OpenSubsystems s.r.o. Slovak Republic. All rights reserved.
*
* Project: OpenSubsystems
*
* $Id: FileUtils.java,v 1.12 2007/02/01 07:18:32 bastafidli Exp $
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.Properties;
import java.util.logging.Logger;
/**
* Collection of methods to make work with files easier.
*
* @version $Id: FileUtils.java,v 1.12 2007/02/01 07:18:32 bastafidli Exp $
* @author Miro Halas
* @code.reviewer Miro Halas
* @code.reviewed 1.7 2006/05/21 03:45:37 bastafidli
*/
public class FileUtils
{
// Configuration settings ///////////////////////////////////////////////////
/**
* Default 10 digit file storage distribution array. This means that if I
* want to name file as 10 digit number e.g. number 123 as 0000000123 or
* number 123456789 as 01234567890. Then the path constructed from number
* 1234567890 using distribution 2/2/2/4 would be 12/34/56/0123456789
*/
public static final int[] DEFAULT_STRORAGE_TREE_DISTRIBUTION = {2, 2, 2, 4};
/**
* How big buffer to use to process files.
*/
public static final int BUFFER_SIZE = 65536;
// Cached values ////////////////////////////////////////////////////////////
/**
* Temporary directory to use. It is guarantee that it ends with \ (or /)
*/
protected static String s_strTempDirectory;
// Constructors /////////////////////////////////////////////////////////////
/**
* Move file to a new location. If the destination is on different volume,
* this file will be copied and then original file will be deleted.
* If the destination already exists, this method renames it with different
* name and leaves it in that directory and moves the new file along side
* the renamed one.
*
* @param flCurrent - file to move
* @param flDestination - destination file
* @throws IOException - error message
* @throws OSSException - error message
*/
public static void moveFile(
File flCurrent,
File flDestination
) throws IOException
{
// Make sure that the source exist, it might be already moved from
// a directory and we just don"t know about it
if (flCurrent.exists())
{
// Next check if the destination file exists
if (flDestination.exists())
{
// If the destination exists, that means something went wrong
// Rename the destination file under temporaty name and try to
// move the new file instead of it
renameToTemporaryName(flDestination, "old");
}
// Make sure the directory exists and if not create it
File flFolder;
flFolder = flDestination.getParentFile();
if ((flFolder != null) && (!flFolder.exists()))
{
if (!flFolder.mkdirs())
{
// Do not throw the exception if the directory already exists
// because it was created meanwhile for example by a different
// thread
if (!flFolder.exists())
{
throw new IOException("Cannot create directory " + flFolder);
}
}
}
// Now everything should exist so try to rename the file first
// After testing, this renames files even between volumes C to H
// so we don"t have to do anything else on Windows but we still
// have to handle erro on Unix
if (!flCurrent.renameTo(flDestination))
{
// Try to copy and delete since the rename doesn"t work on Solaris
// between file systems
copyFile(flCurrent, flDestination);
// Now delete the file
if (!flCurrent.delete())
{
// Delete the destination file first since we haven"t really moved
// the file
flDestination.delete();
throw new IOException("Cannot delete already copied file " + flCurrent);
}
}
}
}
/**
* Copy the current file to the destination file.
*
* @param flCurrent - source file
* @param flDestination - destination file
* @throws IOException - error message
* @throws OSSException - error message
*/
public static void copyFile(
File flCurrent,
File flDestination
) throws IOException
{
// Make sure the directory exists and if not create it
File flFolder;
flFolder = flDestination.getParentFile();
if ((flFolder != null) && (!flFolder.exists()))
{
if (!flFolder.mkdirs())
{
// Do not throw the exception if the directory already exists
// because it was created meanwhile for example by a different
// thread
if (!flFolder.exists())
{
throw new IOException("Cannot create directory " + flFolder);
}
}
}
// FileChannel srcChannel = null;
// FileChannel dstChannel = null;
FileInputStream finInput = null;
//MHALAS: This code is not working reliably on Solaris 8 with 1.4.1_01
// Getting exceptions from native code
/*
// Create channel on the source
srcChannel = new FileInputStream(flCurrent).getChannel();
// Create channel on the destination
dstChannel = new FileOutputStream(flDestination).getChannel();
// Copy file contents from source to destination
dstChannel.transferFrom(srcChannel, 0, srcChannel.size());
Don"t forget to close the channels if you enable this code again
*/
try
{
finInput = new FileInputStream(flCurrent);
}
catch (IOException ioExec)
{
if (finInput != null)
{
try
{
finInput.close();
}
catch (Throwable thr)
{
}
}
throw ioExec;
}
FileUtils.copyStreamToFile(finInput, flDestination);
}
/**
* Rename the file to temporaty name with given prefix
*
* @param flFileToRename - file to rename
* @param strPrefix - prefix to use
* @throws IOException - error message
*/
public static void renameToTemporaryName(
File flFileToRename,
String strPrefix
) throws IOException
{
assert strPrefix != null : "Prefix cannot be null.";
String strParent;
StringBuffer sbBuffer = new StringBuffer();
File flTemp;
int iIndex = 0;
strParent = flFileToRename.getParent();
// Generate new name for the file in a deterministic way
do
{
iIndex++;
sbBuffer.delete(0, sbBuffer.length());
if (strParent != null)
{
sbBuffer.append(strParent);
sbBuffer.append(File.separatorChar);
}
sbBuffer.append(strPrefix);
sbBuffer.append("_");
sbBuffer.append(iIndex);
sbBuffer.append("_");
sbBuffer.append(flFileToRename.getName());
flTemp = new File(sbBuffer.toString());
}
while (flTemp.exists());
// Now we should have unique name
if (!flFileToRename.renameTo(flTemp))
{
throw new IOException("Cannot rename " + flFileToRename.getAbsolutePath()
+ " to " + flTemp.getAbsolutePath());
}
}
/**
* Delete all files and directories in directory but do not delete the
* directory itself.
*
* @param strDir - string that specifies directory to delete
* @return boolean - sucess flag
*/
public static boolean deleteDirectoryContent(
String strDir
)
{
return ((strDir != null) && (strDir.length() > 0))
? deleteDirectoryContent(new File(strDir)) : false;
}
/**
* Delete all files and directories in directory but do not delete the
* directory itself.
*
* @param fDir - directory to delete
* @return boolean - sucess flag
*/
public static boolean deleteDirectoryContent(
File fDir
)
{
boolean bRetval = false;
if (fDir != null && fDir.isDirectory())
{
File[] files = fDir.listFiles();
if (files != null)
{
bRetval = true;
boolean dirDeleted;
for (int index = 0; index < files.length; index++)
{
if (files[index].isDirectory())
{
// TODO: Performance: Implement this as a queue where you add to
// the end and take from the beginning, it will be more efficient
// than the recursion
dirDeleted = deleteDirectoryContent(files[index]);
if (dirDeleted)
{
bRetval = bRetval && files[index].delete();
}
else
{
bRetval = false;
}
}
else
{
bRetval = bRetval && files[index].delete();
}
}
}
}
return bRetval;
}
/**
* Deletes all files and subdirectories under the specified directory including
* the specified directory
*
* @param strDir - string that specifies directory to be deleted
* @return boolean - true if directory was successfully deleted
*/
public static boolean deleteDir(
String strDir
)
{
return ((strDir != null) && (strDir.length() > 0))
? deleteDir(new File(strDir)) : false;
}
/**
* Deletes all files and subdirectories under the specified directory including
* the specified directory
*
* @param fDir - directory to be deleted
* @return boolean - true if directory was successfully deleted
*/
public static boolean deleteDir(
File fDir
)
{
boolean bRetval = false;
if (fDir != null && fDir.exists())
{
bRetval = deleteDirectoryContent(fDir);
if (bRetval)
{
bRetval = bRetval && fDir.delete();
}
}
return bRetval;
}
/**
* Compare binary files. Both files must be files (not directories) and exist.
*
* @param first - first file
* @param second - second file
* @return boolean - true if files are binery equal
* @throws IOException - error in function
*/
public boolean isFileBinaryEqual(
File first,
File second
) throws IOException
{
// TODO: Test: Missing test
boolean retval = false;
if ((first.exists()) && (second.exists())
&& (first.isFile()) && (second.isFile()))
{
if (first.getCanonicalPath().equals(second.getCanonicalPath()))
{
retval = true;
}
else
{
FileInputStream firstInput = null;
FileInputStream secondInput = null;
BufferedInputStream bufFirstInput = null;
BufferedInputStream bufSecondInput = null;
try
{
firstInput = new FileInputStream(first);
secondInput = new FileInputStream(second);
bufFirstInput = new BufferedInputStream(firstInput, BUFFER_SIZE);
bufSecondInput = new BufferedInputStream(secondInput, BUFFER_SIZE);
int firstByte;
int secondByte;
while (true)
{
firstByte = bufFirstInput.read();
secondByte = bufSecondInput.read();
if (firstByte != secondByte)
{
break;
}
if ((firstByte < 0) && (secondByte < 0))
{
retval = true;
break;
}
}
}
finally
{
try
{
if (bufFirstInput != null)
{
bufFirstInput.close();
}
}
finally
{
if (bufSecondInput != null)
{
bufSecondInput.close();
}
}
}
}
}
return retval;
}
/**
* Get path which represents temporary directory. It is guarantee that it
* ends with \ (or /).
*
* @return String
*/
public static String getTemporaryDirectory(
)
{
return s_strTempDirectory;
}
/**
* Copy any input stream to output file. Once the data will be copied
* the stream will be closed.
*
* @param input - InputStream to copy from
* @param output - File to copy to
* @throws IOException - error in function
* @throws OSSMultiException - double error in function
*/
public static void copyStreamToFile(
InputStream input,
File output
) throws IOException
{
FileOutputStream foutOutput = null;
// open input file as stream safe - it can throw some IOException
try
{
foutOutput = new FileOutputStream(output);
}
catch (IOException ioExec)
{
if (foutOutput != null)
{
try
{
foutOutput.close();
}
catch (IOException ioExec2)
{
}
}
throw ioExec;
}
// all streams including os are closed in copyStreamToStream function
// in any case
copyStreamToStream(input, foutOutput);
}
/**
* Copy any input stream to output stream. Once the data will be copied
* both streams will be closed.
*
* @param input - InputStream to copy from
* @param output - OutputStream to copy to
* @throws IOException - io error in function
* @throws OSSMultiException - double error in function
*/
public static void copyStreamToStream(
InputStream input,
OutputStream output
) throws IOException
{
InputStream is = null;
OutputStream os = null;
int ch;
try
{
if (input instanceof BufferedInputStream)
{
is = input;
}
else
{
is = new BufferedInputStream(input);
}
if (output instanceof BufferedOutputStream)
{
os = output;
}
else
{
os = new BufferedOutputStream(output);
}
while ((ch = is.read()) != -1)
{
os.write(ch);
}
os.flush();
}
finally
{
IOException exec1 = null;
IOException exec2 = null;
try
{
// because this close can throw exception we do next close in
// finally statement
if (os != null)
{
try
{
os.close();
}
catch (IOException exec)
{
exec1 = exec;
}
}
}
finally
{
if (is != null)
{
try
{
is.close();
}
catch (IOException exec)
{
exec2 = exec;
}
}
}
if ((exec1 != null) && (exec2 != null))
{
throw exec1;
}
else if (exec1 != null)
{
throw exec1;
}
else if (exec2 != null)
{
throw exec2;
}
}
}
}
Program to empty a directory
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
/**
* DANGEROUS Program to empty a directory.
*
* @author Ian Darwin, Learning Tree, Course 471/478
*/
public class Empty {
public static void main(String[] argv) {
if (argv.length != 1) { // no progname in argv[0]
System.err.println("usage: Empty dirname");
System.exit(1);
}
File dir = new File(argv[0]);
if (!dir.exists()) {
System.out.println(argv[0] + " does not exist");
return;
}
String[] info = dir.list();
for (int i = 0; i < info.length; i++) {
File n = new File(argv[0] + dir.separator + info[i]);
if (!n.isFile()) // skip ., .., other directories too
continue;
System.out.println("removing " + n.getPath());
if (!n.delete())
System.err.println("Couldn"t remove " + n.getPath());
}
}
}
Program to remove files matching a name in a directory
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
/**
* DANGEROUS Program to remove files matching a name in a directory
*
* @author Ian Darwin, http://www.darwinsys.ru/
*/
public class KillFilesByName {
public static void main(String[] argv) {
if (argv.length != 2) {
System.err.println("usage: KillFilesByName dirname pattern");
System.exit(1);
}
File dir = new File(argv[0]);
if (!dir.exists()) {
System.out.println(argv[0] + " does not exist");
return;
}
String patt = argv[1];
String[] info = dir.list();
for (int i = 0; i < info.length; i++) {
File n = new File(argv[0] + dir.separator + info[i]);
if (!n.isFile()) { // skip ., .., other directories, etc.
continue;
}
if (info[i].indexOf(patt) == -1) { // name doesn"t match
continue;
}
System.out.println("removing " + n.getPath());
if (!n.delete())
System.err.println("Couldn"t remove " + n.getPath());
}
}
}
Readonly Files
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002. All rights
* reserved. Software written by Ian F. Darwin and others. $Id: LICENSE,v 1.8
* 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer. 2. Redistributions in
* binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS"" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee cup"
* logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
import java.io.IOException;
public class ReadOnly {
public static void main(String[] a) throws IOException {
File f = new File("f");
if (!f.createNewFile()) {
System.out.println("Can"t create new file.");
return;
}
if (!f.canWrite()) {
System.out.println("Can"t write new file!");
return;
}
if (!f.setReadOnly()) {
System.out.println("Grrr! Can"t set file read-only.");
return;
}
if (f.canWrite()) {
System.out.println("Most immutable, captain!");
System.out
.println("But it still says canWrite() after setReadOnly");
return;
} else {
System.out.println("Logical, captain!");
System.out
.println("canWrite() correctly returns false after setReadOnly");
}
}
}
Rename a file in Java
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
import java.io.IOException;
/**
* Rename a file in Java
*
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: Rename.java,v 1.4 2004/02/09 03:33:47 ian Exp $
*/
public class Rename {
public static void main(String[] argv) throws IOException {
// Construct the file object. Does NOT create a file on disk!
File f = new File("Rename.java~"); // backup of this source file.
// Rename the backup file to "junk.dat"
// Renaming requires a File object for the target.
f.renameTo(new File("junk.dat"));
}
}
Report on a file"s status in Java
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.File;
import java.io.IOException;
import java.util.Date;
/**
* Report on a file"s status in Java
*
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: FileStatus.java,v 1.6 2004/03/11 03:25:35 ian Exp $
*/
public class FileStatus {
public static void main(String[] argv) throws IOException {
// Ensure that a filename (or something) was given in argv[0]
if (argv.length == 0) {
System.err.println("Usage: FileStatus filename");
System.exit(1);
}
for (int i = 0; i < argv.length; i++) {
status(argv[i]);
}
}
public static void status(String fileName) throws IOException {
System.out.println("---" + fileName + "---");
// Construct a File object for the given file.
File f = new File(fileName);
// See if it actually exists
if (!f.exists()) {
System.out.println("file not found");
System.out.println(); // Blank line
return;
}
// Print full name
System.out.println("Canonical name " + f.getCanonicalPath());
// Print parent directory if possible
String p = f.getParent();
if (p != null) {
System.out.println("Parent directory: " + p);
}
// Check if the file is readable
if (f.canRead()) {
System.out.println("File is readable.");
}
// Check if the file is writable
if (f.canWrite()) {
System.out.println("File is writable.");
}
// Report on the modification time.
Date d = new Date();
d.setTime(f.lastModified());
System.out.println("Last modified " + d);
// See if file, directory, or other. If file, print size.
if (f.isFile()) {
// Report on the file"s size
System.out.println("File size is " + f.length() + " bytes.");
} else if (f.isDirectory()) {
System.out.println("It"s a directory");
} else {
System.out.println("I dunno! Neither a file nor a directory!");
}
System.out.println(); // blank line between entries
}
}
Return readable file size with selected value measure
/**
* Methods for files and folders treatment.
*
* @author Cyril JOUI
*/
public final class FileUtil {
/**
* @param fileSize
* file size to convert and format to string.
* @return return readable file size with selected value measure
*/
public static String getReadableFileSize(final long fileSize) {
double l = fileSize * 1D;
String s = "";
if (l < 1000) {
s = fileSize + " B";
} else {
l = l / 1024D;
if (l < 1000) {
s = l + " KB";
} else {
l = l / 1024D;
if (l < 1000) {
s = l + " MB";
} else {
l = l / 1024D;
s = l + " GB";
}
}
}
return (s.length() - s.indexOf(".") <= 3 ? s : s.substring(0, s.indexOf(".") + 3))
+ s.substring(s.indexOf(" "), s.length());
}
}
Simple directory lister
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
/**
* Simple directory lister.
*
* @author Ian Darwin, http://www.darwinsys.ru/
* @version $Id: Ls.java,v 1.3 2004/02/09 03:33:47 ian Exp $
*/
public class Ls {
public static void main(String argh_my_aching_fingers[]) {
String[] dir = new java.io.File(".").list(); // Get list of names
java.util.Arrays.sort(dir); // Sort it (Data Structuring chapter))
for (int i = 0; i < dir.length; i++)
System.out.println(dir[i]); // Print the list
}
}
TeePrintStream tees all PrintStream operations into a file, rather like the UNIX tee(1) command
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
/**
* TeePrintStream tees all PrintStream operations into a file, rather like the
* UNIX tee(1) command. It is a PrintStream subclass. The expected usage would
* be something like the following:
*
* <PRE>
*
* ... TeePrintStream ts = new TeePrintStream(System.err, "err.log");
* System.setErr(ts); // ...lots of code that occasionally writes to
* System.err... ts.close(); ...
*
* <PRE>
*
* <P>
* I only override Constructors, the write(), check() and close() methods, since
* any of the print() or println() methods must go through these. Thanks to
* Svante Karlsson for help formulating this.
*
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: TeePrintStream.java,v 1.5 2004/02/08 23:57:29 ian Exp $
*/
public class TeePrintStream extends PrintStream {
protected PrintStream parent;
protected String fileName;
/** A simple test case. */
public static void main(String[] args) throws IOException {
TeePrintStream ts = new TeePrintStream(System.err, "err.log", true);
System.setErr(ts);
System.err.println("An imitation error message");
ts.close();
}
/**
* Construct a TeePrintStream given an existing PrintStream, an opened
* OutputStream, and a boolean to control auto-flush. This is the main
* constructor, to which others delegate via "this".
*/
public TeePrintStream(PrintStream orig, OutputStream os, boolean flush)
throws IOException {
super(os, true);
fileName = "(opened Stream)";
parent = orig;
}
/**
* Construct a TeePrintStream given an existing PrintStream and an opened
* OutputStream.
*/
public TeePrintStream(PrintStream orig, OutputStream os) throws IOException {
this(orig, os, true);
}
/*
* Construct a TeePrintStream given an existing Stream and a filename.
*/
public TeePrintStream(PrintStream os, String fn) throws IOException {
this(os, fn, true);
}
/*
* Construct a TeePrintStream given an existing Stream, a filename, and a
* boolean to control the flush operation.
*/
public TeePrintStream(PrintStream orig, String fn, boolean flush)
throws IOException {
this(orig, new FileOutputStream(fn), flush);
}
/** Return true if either stream has an error. */
public boolean checkError() {
return parent.checkError() || super.checkError();
}
/** override write(). This is the actual "tee" operation. */
public void write(int x) {
parent.write(x); // "write once;
super.write(x); // write somewhere else."
}
/** override write(). This is the actual "tee" operation. */
public void write(byte[] x, int o, int l) {
parent.write(x, o, l); // "write once;
super.write(x, o, l); // write somewhere else."
}
/** Close both streams. */
public void close() {
parent.close();
super.close();
}
/** Flush both streams. */
public void flush() {
parent.flush();
super.flush();
}
}
Touch: set File Last Modified Time
import java.io.File;
import java.util.Date;
class Touch {
public static void main(String[] args) {
String[] names = new File(".").list();
Date current = new Date();
for (int i = 0; i < names.length; i++) {
File f = new File(names[i]);
f.setLastModified(current.getTime());
}
}
}
Undent - remove leading spaces
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.*;
/** Undent - remove leading spaces
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: Undent.java,v 1.5 2004/02/08 23:57:09 ian Exp $
*/
public class Undent {
//+
/** the default number of spaces to remove. */
int nSpaces = 2;
//-
public static void main(String[] av) {
Undent c = new Undent();
if (av.length == 0)
c.process(new BufferedReader(
new InputStreamReader(System.in)));
else for (int i=0; i<av.length; i++) {
try {
c.process(new BufferedReader(new FileReader(av[i])));
} catch (FileNotFoundException e) {
System.err.println(e);
}
}
}
/** undent one file, given an open BufferedReader.
* Undent by removing UP TO "nSpaces" leading spaces.
*/
public void process(BufferedReader is) {
//+
// GRRR THIS DOES NOT QUITE WORK - FIX -- Ian
try {
String inputLine;
while ((inputLine = is.readLine()) != null) {
int i;
for (i=0; i<nSpaces; i++) {
if (!Character.isWhitespace(inputLine.charAt(i)))
break;
}
System.out.println(inputLine.substring(i));
}
is.close();
//-
} catch (IOException e) {
System.out.println("IOException: " + e);
}
}
//-
}
Word Count
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Map;
import java.util.StringTokenizer;
public class WordCount {
static final Integer ONE = new Integer(1);
public static void main(String args[]) throws IOException {
Hashtable map = new Hashtable();
FileReader fr = new FileReader(args[0]);
BufferedReader br = new BufferedReader(fr);
String line;
while ((line = br.readLine()) != null) {
processLine(line, map);
}
Enumeration e = map.keys();
while (e.hasMoreElements()) {
String key = (String) e.nextElement();
System.out.println(key + " : " + map.get(key));
}
}
static void processLine(String line, Map map) {
StringTokenizer st = new StringTokenizer(line);
while (st.hasMoreTokens()) {
addWord(map, st.nextToken());
}
}
static void addWord(Map map, String word) {
Object obj = map.get(word);
if (obj == null) {
map.put(word, ONE);
} else {
int i = ((Integer) obj).intValue() + 1;
map.put(word, new Integer(i));
}
}
}
