Java/File Input Output/Data Input Output

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Controlling serialization by adding your own writeObject() and readObject() methods

   <source lang="java">

// : c12:SerialCtl.java // Controlling serialization by adding your own // writeObject() and readObject() methods. // From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002 // www.BruceEckel.ru. See copyright notice in CopyRight.txt. import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; public class SerialCtl implements Serializable { 

 private String a;
 private transient String b;
 public SerialCtl(String aa, String bb) {
   a = "Not Transient: " + aa;
   b = "Transient: " + bb;
 }
 public String toString() {
   return a + "\n" + b;
 }
 private void writeObject(ObjectOutputStream stream) throws IOException {
   stream.defaultWriteObject();
   stream.writeObject(b);
 }
 private void readObject(ObjectInputStream stream) throws IOException,
     ClassNotFoundException {
   stream.defaultReadObject();
   b = (String) stream.readObject();
 }
 public static void main(String[] args) throws IOException,
     ClassNotFoundException {
   SerialCtl sc = new SerialCtl("Test1", "Test2");
   System.out.println("Before:\n" + sc);
   ByteArrayOutputStream buf = new ByteArrayOutputStream();
   ObjectOutputStream o = new ObjectOutputStream(buf);
   o.writeObject(sc);
   // Now get it back:
   ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(
       buf.toByteArray()));
   SerialCtl sc2 = (SerialCtl) in.readObject();
   System.out.println("After:\n" + sc2);
 }

} ///:~ 


      </source>



Data IO Demo

   <source lang="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.DataInputStream; import java.io.DataOutputStream; import java.io.EOFException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class DataIODemo { 

 public static void main(String[] args) throws IOException {
   // write the data out
   DataOutputStream out = new DataOutputStream(new FileOutputStream(
       "invoice1.txt"));
   double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
   int[] units = { 12, 8, 13, 29, 50 };
   String[] descs = { "Java T-shirt", "Java Mug", "Duke Juggling Dolls",
       "Java Pin", "Java Key Chain" };
   for (int i = 0; i < prices.length; i++) {
     out.writeDouble(prices[i]);
     out.writeChar("\t");
     out.writeInt(units[i]);
     out.writeChar("\t");
     out.writeChars(descs[i]);
     out.writeChar("\n");
   }
   out.close();
   // read it in again
   DataInputStream in = new DataInputStream(new FileInputStream(
       "invoice1.txt"));
   double price;
   int unit;
   StringBuffer desc;
   double total = 0.0;
   try {
     while (true) {
       price = in.readDouble();
       in.readChar(); // throws out the tab
       unit = in.readInt();
       in.readChar(); // throws out the tab
       char chr;
       desc = new StringBuffer(20);
       char lineSep = System.getProperty("line.separator").charAt(0);
       while ((chr = in.readChar()) != lineSep)
         desc.append(chr);
       System.out.println("You"ve ordered " + unit + " units of "
           + desc + " at $" + price);
       total = total + unit * price;
     }
   } catch (EOFException e) {
   }
   System.out.println("For a TOTAL of: $" + total);
   in.close();
 }

} 

      </source>



Data IO Test

   <source lang="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.DataInputStream; import java.io.DataOutputStream; import java.io.EOFException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class DataIOTest { 

 public static void main(String[] args) throws IOException {
   // write the data out
   DataOutputStream out = new DataOutputStream(new FileOutputStream(
       "invoice1.txt"));
   double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
   int[] units = { 12, 8, 13, 29, 50 };
   String[] descs = { "Java T-shirt", "Java Mug", "Duke Juggling Dolls",
       "Java Pin", "Java Key Chain" };
   for (int i = 0; i < prices.length; i++) {
     out.writeDouble(prices[i]);
     out.writeChar("\t");
     out.writeInt(units[i]);
     out.writeChar("\t");
     out.writeChars(descs[i]);
     out.writeChar("\n");
   }
   out.close();
   // read it in again
   DataInputStream in = new DataInputStream(new FileInputStream(
       "invoice1.txt"));
   double price;
   int unit;
   StringBuffer desc;
   double total = 0.0;
   try {
     while (true) {
       price = in.readDouble();
       in.readChar(); // throws out the tab
       unit = in.readInt();
       in.readChar(); // throws out the tab
       char chr;
       desc = new StringBuffer(20);
       char lineSep = System.getProperty("line.separator").charAt(0);
       while ((chr = in.readChar()) != lineSep)
         desc.append(chr);
       System.out.println("You"ve ordered " + unit + " units of "
           + desc + " at $" + price);
       total = total + unit * price;
     }
   } catch (EOFException e) {
   }
   System.out.println("For a TOTAL of: $" + total);
   in.close();
 }

} 

      </source>



Data IO Test 2

   <source lang="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.EOFException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; public class DataIOTest2 { 

 public static void main(String[] args) throws IOException {
   // write the data out
   ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(
       "invoice1.txt"));
   double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
   int[] units = { 12, 8, 13, 29, 50 };
   String[] descs = { "Java T-shirt", "Java Mug", "Duke Juggling Dolls",
       "Java Pin", "Java Key Chain" };
   for (int i = 0; i < prices.length; i++) {
     out.writeDouble(prices[i]);
     out.writeChar("\t");
     out.writeInt(units[i]);
     out.writeChar("\t");
     out.writeChars(descs[i]);
     out.writeChar("\n");
   }
   out.close();
   // read it in again
   ObjectInputStream in = new ObjectInputStream(new FileInputStream(
       "invoice1.txt"));
   double price;
   int unit;
   String desc;
   double total = 0.0;
   try {
     while (true) {
       price = in.readDouble();
       in.readChar(); // throws out the tab
       unit = in.readInt();
       in.readChar(); // throws out the tab
       desc = in.readLine();
       System.out.println("You"ve ordered " + unit + " units of "
           + desc + " at $" + price);
       total = total + unit * price;
     }
   } catch (EOFException e) {
   }
   System.out.println("For a TOTAL of: $" + total);
   in.close();
 }

} 

      </source>



IO demo: DataOutputStream and DataInputStream

   <source lang="java">

import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.EOFException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class DataIODemo1 { 

 public static void main(String[] args) throws IOException {
   DataOutputStream out = new DataOutputStream(new FileOutputStream(
       "jexp.txt"));
   double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
   int[] units = { 12, 8, 13, 29, 50 };
   String[] descs = { "Java", "Source ", "and",
       "Support."};
   for (int i = 0; i < prices.length; i++) {
     out.writeDouble(prices[i]);
     out.writeChar("\t");
     out.writeInt(units[i]);
     out.writeChar("\t");
     out.writeChars(descs[i]);
     out.writeChar("\n");
   }
   out.close();
   // read it in again
   DataInputStream in = new DataInputStream(new FileInputStream(
       "jexp.txt"));
   double price;
   int unit;
   String desc;
   double total = 0.0;
   try {
     while (true) {
       price = in.readDouble();
       in.readChar(); // throws out the tab
       unit = in.readInt();
       in.readChar(); // throws out the tab
       desc = in.readLine();
       System.out.println( unit );
       System.out.println( desc );
       System.out.println( desc );
       total = total + unit * price;
     }
   } catch (EOFException e) {
   }
   in.close();
 }

} 

      </source>



ProgressMonitorInputStream Demo

   <source lang="java">

import java.awt.Color; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.InputStreamReader; import javax.swing.JLabel; import javax.swing.ProgressMonitorInputStream; public class ProgressInputSample { 

 public static final int NORMAL = 0;
 public static void main(String args[]) throws Exception {
   int returnValue = NORMAL;
   if (args.length != 1) {
     System.err.println("Usage:");
     System.err.println("java ProgressInput filename");
   } else {
     FileInputStream fis = new FileInputStream(args[0]);
     JLabel filenameLabel = new JLabel(args[0], JLabel.RIGHT);
     filenameLabel.setForeground(Color.black);
     Object message[] = { "Reading:", filenameLabel };
     ProgressMonitorInputStream pmis = new ProgressMonitorInputStream(null, message, fis);
     InputStreamReader isr = new InputStreamReader(pmis);
     BufferedReader br = new BufferedReader(isr);
     String line;
     while ((line = br.readLine()) != null) {
       System.out.println(line);
       Thread.sleep(500);
     }
     br.close();
   }
   // AWT Thread created - must exit
   System.exit(returnValue);
 }

} 

      </source>



Read Write Lock Test

   <source lang="java">

/* Software Architecture Design Patterns in Java by Partha Kuchana Auerbach Publications

  • /

public class ReadWriteLockTest { 

 public static void main(String[] args) {
   Item item = new Item("CompScience-I");
   new MemberTransaction("Member1", item, "StatusCheck");
   new MemberTransaction("Member2", item, "StatusCheck");
   new MemberTransaction("Member3", item, "CheckOut");
   new MemberTransaction("Member4", item, "CheckOut");
   new MemberTransaction("Member5", item, "CheckOut");
   new MemberTransaction("Member6", item, "StatusCheck");
 }

} class Item { 

 private String name;
 private ReadWriteLock rwLock;
 private String status;
 public Item(String n) {
   name = n;
   rwLock = new ReadWriteLock();
   status = "N";
 }
 public void checkOut(String member) {
   rwLock.getWriteLock();
   status = "Y";
   System.out.println(member + " has been issued a write lock-ChkOut");
   rwLock.done();
 }
 public String getStatus(String member) {
   rwLock.getReadLock();
   System.out.println(member + " has been issued a read lock");
   rwLock.done();
   return status;
 }
 public void checkIn(String member) {
   rwLock.getWriteLock();
   status = "N";
   System.out.println(member + " has been issued a write lock-ChkIn");
   rwLock.done();
 }

} class ReadWriteLock { 

 private Object lockObj;
 private int totalReadLocksGiven;
 private boolean writeLockIssued;
 private int threadsWaitingForWriteLock;
 public ReadWriteLock() {
   lockObj = new Object();
   writeLockIssued = false;
 }
 /*
  * A read lock can be issued if there is no currently issued write lock and
  * there is no thread(s) currently waiting for the write lock
  */
 public void getReadLock() {
   synchronized (lockObj) {
     while ((writeLockIssued) || (threadsWaitingForWriteLock != 0)) {
       try {
         lockObj.wait();
       } catch (InterruptedException e) {
         //
       }
     }
     //System.out.println(" Read Lock Issued");
     totalReadLocksGiven++;
   }
 }
 /*
  * A write lock can be issued if there is no currently issued read or write
  * lock
  */
 public void getWriteLock() {
   synchronized (lockObj) {
     threadsWaitingForWriteLock++;
     while ((totalReadLocksGiven != 0) || (writeLockIssued)) {
       try {
         lockObj.wait();
       } catch (InterruptedException e) {
         //
       }
     }
     //System.out.println(" Write Lock Issued");
     threadsWaitingForWriteLock--;
     writeLockIssued = true;
   }
 }
 //used for releasing locks
 public void done() {
   synchronized (lockObj) {
     //check for errors
     if ((totalReadLocksGiven == 0) && (!writeLockIssued)) {
       System.out.println(" Error: Invalid call to release the lock");
       return;
     }
     if (writeLockIssued)
       writeLockIssued = false;
     else
       totalReadLocksGiven--;
     lockObj.notifyAll();
   }
 }

} class MemberTransaction extends Thread { 

 private String name;
 private Item item;
 private String operation;
 public MemberTransaction(String n, Item i, String p) {
   name = n;
   item = i;
   operation = p;
   start();
 }
 public void run() {
   //all members first read the status
   item.getStatus(name);
   if (operation.equals("CheckOut")) {
     System.out.println("\n" + name + " is ready to checkout the item.");
     item.checkOut(name);
     try {
       sleep(1);
     } catch (InterruptedException e) {
       //
     }
     item.checkIn(name);
   }
 }

} 

      </source>



ScanStreamTok - show scanning a file with StringTokenizer

   <source lang="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.FileReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.Reader; import java.io.StreamTokenizer; /** 

* ScanStreamTok - show scanning a file with StringTokenizer.
*
* @author  Ian Darwin, http://www.darwinsys.ru/
* @version  $Id: ScanStreamTok.java,v 1.6 2004/02/17 00:17:54 ian Exp $
*/

public class ScanStreamTok { 

 protected  StreamTokenizer tf;
 public static void main(String[] av) throws IOException {
   if (av.length == 0)
     new ScanStreamTok(
       new InputStreamReader(System.in)).process();
   else 
     for (int i=0; i<av.length; i++)
       new ScanStreamTok(av[i]).process();
 }
 /** Construct a file scanner by name */
 public ScanStreamTok(String fileName) throws IOException {
   tf = new StreamTokenizer(new FileReader(fileName));
 }
 /** Construct a file scanner by existing Reader */
 public ScanStreamTok(Reader rdr) throws IOException {
   tf = new StreamTokenizer(rdr);
 }
 protected void process() throws IOException {
   String s = null;
   int i;
   while ((i = tf.nextToken()) != StreamTokenizer.TT_EOF) {
     switch(i) {
     case StreamTokenizer.TT_EOF:
       System.out.println("End of file");
       break;
     case StreamTokenizer.TT_EOL:
       System.out.println("End of line");
       break;
     case StreamTokenizer.TT_NUMBER:
       System.out.println("Number " + tf.nval);
       break;
     case StreamTokenizer.TT_WORD:
       System.out.println("Word, length " + tf.sval.length() + "->" + tf.sval);
       break;
     default:
       System.out.println("What is it? i = " + i);
     }
   }
 }

} 


      </source>



Some simple file I-O primitives reimplemented in Java

   <source lang="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.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.PrintWriter; import java.io.Reader; import java.io.Writer; /** 

* Some simple file I-O primitives reimplemented in Java. All methods are
* static, since there is no state.
* 
* @version $Id: FileIO.java,v 1.18 2004/05/30 01:39:27 ian Exp $
*/

public class FileIO { 

 /** Nobody should need to create an instance; all methods are static */
 private FileIO() {
   // Nothing to do
 }
 /** Copy a file from one filename to another */
 public static void copyFile(String inName, String outName)
     throws FileNotFoundException, IOException {
   BufferedInputStream is = new BufferedInputStream(new FileInputStream(
       inName));
   BufferedOutputStream os = new BufferedOutputStream(
       new FileOutputStream(outName));
   copyFile(is, os, true);
 }
 /** Copy a file from an opened InputStream to opened OutputStream */
 public static void copyFile(InputStream is, OutputStream os, boolean close)
     throws IOException {
   byte[] b = new byte[BLKSIZ]; // the byte read from the file
   int i;
   while ((i = is.read(b)) != -1) {
     os.write(b, 0, i);
   }
   is.close();
   if (close)
     os.close();
 }
 /** Copy a file from an opened Reader to opened Writer */
 public static void copyFile(Reader is, Writer os, boolean close)
     throws IOException {
   int b; // the byte read from the file
   BufferedReader bis = new BufferedReader(is);
   while ((b = is.read()) != -1) {
     os.write(b);
   }
   is.close();
   if (close)
     os.close();
 }
 /** Copy a file from a filename to a PrintWriter. */
 public static void copyFile(String inName, PrintWriter pw, boolean close)
     throws FileNotFoundException, IOException {
   BufferedReader ir = new BufferedReader(new FileReader(inName));
   copyFile(ir, pw, close);
 }
 /** Open a file and read the first line from it. */
 public static String readLine(String inName) throws FileNotFoundException,
     IOException {
   BufferedReader is = new BufferedReader(new FileReader(inName));
   String line = null;
   line = is.readLine();
   is.close();
   return line;
 }
 /** The size of blocking to use */
 protected static final int BLKSIZ = 16384;
 /**
  * Copy a data file from one filename to another, alternate method. As the
  * name suggests, use my own buffer instead of letting the BufferedReader
  * allocate and use the buffer.
  */
 public void copyFileBuffered(String inName, String outName)
     throws FileNotFoundException, IOException {
   InputStream is = new FileInputStream(inName);
   OutputStream os = new FileOutputStream(outName);
   int count = 0; // the byte count
   byte[] b = new byte[BLKSIZ]; // the bytes read from the file
   while ((count = is.read(b)) != -1) {
     os.write(b, 0, count);
   }
   is.close();
   os.close();
 }
 /** Read the entire content of a Reader into a String */
 public static String readerToString(Reader is) throws IOException {
   StringBuffer sb = new StringBuffer();
   char[] b = new char[BLKSIZ];
   int n;
   // Read a block. If it gets any chars, append them.
   while ((n = is.read(b)) > 0) {
     sb.append(b, 0, n);
   }
   // Only construct the String object once, here.
   return sb.toString();
 }
 /** Read the content of a Stream into a String */
 public static String inputStreamToString(InputStream is) throws IOException {
   return readerToString(new InputStreamReader(is));
 }
 /** Write a String as the entire content of a File */
 public static void stringToFile(String text, String fileName)
     throws IOException {
   BufferedWriter os = new BufferedWriter(new FileWriter(fileName));
   os.write(text);
   os.flush();
   os.close();
 }
 /** Open a BufferedReader from a named file. */
 public static BufferedReader openFile(String fileName) throws IOException {
   return new BufferedReader(new FileReader(fileName));
 }

} 

      </source>



The use of DataOutputStream and DataInputStream:

   <source lang="java">

import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; class DataIODemo { 

 public static void main(String args[]) throws IOException {
   FileOutputStream fout = new FileOutputStream("Test.dat");
   DataOutputStream out = new DataOutputStream(fout);
   out.writeDouble(98.6);
   out.writeInt(1000);
   out.writeBoolean(true);
   out.close();
   FileInputStream fin = new FileInputStream("Test.dat");
   DataInputStream in = new DataInputStream(fin);
   double d = in.readDouble();
   int i = in.readInt();
   boolean b = in.readBoolean();
   System.out.println("Here are the values:  " + d + " " + i + " " + b);
   in.close();
 }

} 

</source>



Typical I/O stream configurations

   <source lang="java">

// : c12:IOStreamDemo.java // Typical I/O stream configurations. // {RunByHand} // {Clean: IODemo.out,Data.txt,rtest.dat} // From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002 // www.BruceEckel.ru. See copyright notice in CopyRight.txt. import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.ByteArrayInputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.EOFException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.io.RandomAccessFile; import java.io.StringReader; public class IOStreamDemo { 

 // Throw exceptions to console:
 public static void main(String[] args) throws IOException {
   // 1. Reading input by lines:
   BufferedReader in = new BufferedReader(new FileReader(
       "IOStreamDemo.java"));
   String s, s2 = new String();
   while ((s = in.readLine()) != null)
     s2 += s + "\n";
   in.close();
   // 1b. Reading standard input:
   BufferedReader stdin = new BufferedReader(new InputStreamReader(
       System.in));
   System.out.print("Enter a line:");
   System.out.println(stdin.readLine());
   // 2. Input from memory
   StringReader in2 = new StringReader(s2);
   int c;
   while ((c = in2.read()) != -1)
     System.out.print((char) c);
   // 3. Formatted memory input
   try {
     DataInputStream in3 = new DataInputStream(new ByteArrayInputStream(
         s2.getBytes()));
     while (true)
       System.out.print((char) in3.readByte());
   } catch (EOFException e) {
     System.err.println("End of stream");
   }
   // 4. File output
   try {
     BufferedReader in4 = new BufferedReader(new StringReader(s2));
     PrintWriter out1 = new PrintWriter(new BufferedWriter(
         new FileWriter("IODemo.out")));
     int lineCount = 1;
     while ((s = in4.readLine()) != null)
       out1.println(lineCount++ + ": " + s);
     out1.close();
   } catch (EOFException e) {
     System.err.println("End of stream");
   }
   // 5. Storing & recovering data
   try {
     DataOutputStream out2 = new DataOutputStream(
         new BufferedOutputStream(new FileOutputStream("Data.txt")));
     out2.writeDouble(3.14159);
     out2.writeUTF("That was pi");
     out2.writeDouble(1.41413);
     out2.writeUTF("Square root of 2");
     out2.close();
     DataInputStream in5 = new DataInputStream(new BufferedInputStream(
         new FileInputStream("Data.txt")));
     // Must use DataInputStream for data:
     System.out.println(in5.readDouble());
     // Only readUTF() will recover the
     // Java-UTF String properly:
     System.out.println(in5.readUTF());
     // Read the following double and String:
     System.out.println(in5.readDouble());
     System.out.println(in5.readUTF());
   } catch (EOFException e) {
     throw new RuntimeException(e);
   }
   // 6. Reading/writing random access files
   RandomAccessFile rf = new RandomAccessFile("rtest.dat", "rw");
   for (int i = 0; i < 10; i++)
     rf.writeDouble(i * 1.414);
   rf.close();
   rf = new RandomAccessFile("rtest.dat", "rw");
   rf.seek(5 * 8);
   rf.writeDouble(47.0001);
   rf.close();
   rf = new RandomAccessFile("rtest.dat", "r");
   for (int i = 0; i < 10; i++)
     System.out.println("Value " + i + ": " + rf.readDouble());
   rf.close();
 }

} ///:~ 


      </source>



Using transferTo() between channels

   <source lang="java">

// : c12:TransferTo.java // Using transferTo() between channels // {Args: TransferTo.java TransferTo.txt} // {Clean: TransferTo.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.channels.FileChannel; public class TransferTo { 

 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();
   in.transferTo(0, in.size(), out);
   // Or:
   // out.transferFrom(in, 0, in.size());
 }

} ///:~ 


      </source>



Write some data in binary

   <source lang="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.DataOutputStream; import java.io.FileOutputStream; import java.io.IOException; /** 

* Write some data in binary.
* 
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: WriteBinary.java,v 1.3 2004/02/08 23:57:29 ian Exp $
*/

public class WriteBinary { 

 public static void main(String[] argv) throws IOException {
   int i = 42;
   double d = Math.PI;
   String FILENAME = "binary.dat";
   DataOutputStream os = new DataOutputStream(new FileOutputStream(
       FILENAME));
   os.writeInt(i);
   os.writeDouble(d);
   os.close();
   System.out.println("Wrote " + i + ", " + d + " to file " + FILENAME);
 }

} 


      </source>
Источник — «http://jexp.ru/index.php?title=Java/File_Input_Output/Data_Input_Output&oldid=6235»