Java Tutorial/File/FileFilter
Содержание
- 1 A suffix based file filter.
- 2 Create custom File filter
- 3 Custom File Filter
- 4 Files filter that filters files by their suffix (or extension)
- 5 Filter by file
- 6 Filters files based on the extension (what the filename ends with)
- 7 Generic File Filter
- 8 Inverted File Filter
- 9 List file with file filter
- 10 This filter accepts Files that are directories
A suffix based file filter.
/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
import java.io.File;
import java.io.FileFilter;
/**
* A <em>suffix</em> based file filter.
*
* @version <tt>$Revision: 1958 $</tt>
* @author
*/
public class FileSuffixFilter implements FileFilter {
/** A list of suffixes which files must have to be accepted. */
protected final String suffixes[];
/** Flag to signal that we want to ignore the case. */
protected final boolean ignoreCase;
/**
* Construct a <tt>FileSuffixFilter</tt>.
*
* @param suffixes
* A list of suffixes which files mut have to be accepted.
* @param ignoreCase
* <tt>True</tt> if the filter should be case-insensitive.
*/
public FileSuffixFilter(final String suffixes[], final boolean ignoreCase) {
this.ignoreCase = ignoreCase;
if (ignoreCase) {
this.suffixes = new String[suffixes.length];
for (int i = 0; i < suffixes.length; i++) {
this.suffixes[i] = suffixes[i].toLowerCase();
}
} else {
this.suffixes = suffixes;
}
}
/**
* Construct a <tt>FileSuffixFilter</tt>.
*
* @param suffixes
* A list of suffixes which files mut have to be accepted.
*/
public FileSuffixFilter(final String suffixes[]) {
this(suffixes, false);
}
/**
* Construct a <tt>FileSuffixFilter</tt>.
*
* @param suffix
* The suffix which files must have to be accepted.
* @param ignoreCase
* <tt>True</tt> if the filter should be case-insensitive.
*/
public FileSuffixFilter(final String suffix, final boolean ignoreCase) {
this(new String[] { suffix }, ignoreCase);
}
/**
* Construct a case sensitive <tt>FileSuffixFilter</tt>.
*
* @param suffix
* The suffix which files must have to be accepted.
*/
public FileSuffixFilter(final String suffix) {
this(suffix, false);
}
/**
* Check if a file is acceptible.
*
* @param file
* The file to check.
* @return <tt>true</tt> if the file is acceptable.
*/
public boolean accept(final File file) {
boolean success = false;
for (int i = 0; i < suffixes.length && !success; i++) {
if (ignoreCase)
success = file.getName().toLowerCase().endsWith(suffixes[i]);
else
success = file.getName().endsWith(suffixes[i]);
}
return success;
}
}
Create custom File filter
import java.io.File;
import java.io.FileFilter;
public class MainClass {
public static void main(String[] args) {
File cwd = new File(System.getProperty("user.dir"));
File[] htmlFiles = cwd.listFiles(new HTMLFileFilter());
for (int i = 0; i < htmlFiles.length; i++) {
System.out.println(htmlFiles[i]);
}
}
}
class HTMLFileFilter implements FileFilter {
public boolean accept(File pathname) {
if (pathname.getName().endsWith(".html"))
return true;
if (pathname.getName().endsWith(".htm"))
return true;
return false;
}
}
Custom File Filter
import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;
import javax.swing.filechooser.FileFilter;
public class CustomFileFilter extends FileFilter {
private Hashtable filters = null;
private String description = null;
private String fullDescription = null;
private boolean useExtensionsInDescription = true;
public CustomFileFilter() {
this.filters = new Hashtable();
}
public CustomFileFilter(String extension) {
this(extension, null);
}
public CustomFileFilter(String extension, String description) {
this();
if (extension != null)
addExtension(extension);
if (description != null)
setDescription(description);
}
public CustomFileFilter(String[] filters) {
this(filters, null);
}
public CustomFileFilter(String[] filters, String description) {
this();
for (int i = 0; i < filters.length; i++) {
addExtension(filters[i]);
}
if (description != null)
setDescription(description);
}
public boolean accept(File f) {
if (f != null) {
if (f.isDirectory()) {
return true;
}
String extension = getExtension(f);
if (extension != null && filters.get(getExtension(f)) != null) {
return true;
}
}
return false;
}
public String getExtension(File f) {
if (f != null) {
String filename = f.getName();
int i = filename.lastIndexOf(".");
if (i > 0 && i < filename.length() - 1) {
return filename.substring(i + 1).toLowerCase();
}
}
return null;
}
public void addExtension(String extension) {
if (filters == null) {
filters = new Hashtable(5);
}
filters.put(extension.toLowerCase(), this);
fullDescription = null;
}
public String getDescription() {
if (fullDescription == null) {
if (description == null || isExtensionListInDescription()) {
fullDescription = description == null ? "(" : description + " (";
Enumeration extensions = filters.keys();
if (extensions != null) {
fullDescription += "." + (String) extensions.nextElement();
while (extensions.hasMoreElements()) {
fullDescription += ", " + (String) extensions.nextElement();
}
}
fullDescription += ")";
} else {
fullDescription = description;
}
}
return fullDescription;
}
public void setDescription(String description) {
this.description = description;
fullDescription = null;
}
public void setExtensionListInDescription(boolean b) {
useExtensionsInDescription = b;
fullDescription = null;
}
public boolean isExtensionListInDescription() {
return useExtensionsInDescription;
}
}
Files filter that filters files by their suffix (or extension)
/*
* $Id: SuffixFilenameFilter.java,v 1.1.1.1 2005/04/07 18:36:22 pocho Exp $
*/
import java.io.File;
import java.io.FilenameFilter;
import javax.swing.filechooser.FileFilter;
/**
* Files filter that filters files by their suffix (or extension).
* It can be used as file filter for {@link javax.swing.JFileChooser} or
* as file filter for io operations (@link java.io.File#listFiles(java.io.FilenameFilter)}.
*
* @version $Name: $ - $Revision: 1.1.1.1 $ - $Date: 2005/04/07 18:36:22 $
* TODO Test
*/
public class SuffixFilenameFilter extends FileFilter implements FilenameFilter {
/** Suffix of files */
private String suffix;
/** Description of suffix (i.e. .jpg may have description JPG)*/
private String description;
/** Full description of filter - (i.e. JPG (.jpg) */
private String fullDescription;
/** Indicates whether to use suffix in brackets after description */
private boolean useExtensionInDescription = true;
/**
* Creates new instance with a given accepted suffix of file names.
*
* @param suffix used suffix of files (i.e. extension ".xml")
*/
public SuffixFilenameFilter(String suffix) {
this(suffix, null);
}
/**
* Creates new instance with a given accepted suffix of file names.
*
* @param suffix used suffix of files (i.e. extension ".xml")
*/
public SuffixFilenameFilter(String suffix, String description) {
super();
setSuffix(suffix);
setDescription(description);
}
/**
* Indicates whether the name is accepted by this filter or not.
* File must ending with given mask of this filter.
*
* @param dir File
* @param name String
* @return boolean
*/
public boolean accept(File dir, String name){
if (name.lastIndexOf(suffix) > 0)
return true;
else
return false;
}
public boolean accept(File file) {
if (file != null) {
if (file.isDirectory() || accept(file.getParentFile(), file.getName()))
return true;
}
return false;
}
/**
* Returns description of this filter - if {@link #isExtensionInDescription()}
* is <code>true</code> then it creates description in following shape:<br>
* <code>description (suffix)</code>. Otherwise it only returns description.
*
* @see javax.swing.filechooser.FileFilter#getDescription()
*/
public String getDescription() {
if (fullDescription == null && isExtensionInDescription()) {
fullDescription = description==null ? "(" : description + " (";
fullDescription += suffix + ")";
}
return fullDescription;
}
/**
* Sets whether to use suffix in description of this filter.
*
* @param b
*/
public void setExtensionInDescription(boolean b) {
useExtensionInDescription = b;
fullDescription = null;
}
public boolean isExtensionInDescription() {
return useExtensionInDescription;
}
public void setSuffix(String suffix) {
this.suffix = suffix;
fullDescription = null;
}
public void setDescription(String description) {
this.description = description;
fullDescription = null;
}
public String getExtension() {
return suffix;
}
public String getSimpleDescription() {
return description;
}
}
Filter by file
import java.io.File;
import java.io.FileFilter;
import java.io.FilenameFilter;
public class Main {
public static void main(String[] argv) throws Exception {
File dir = new File("c:\\temp");
FileFilter fileFilter = new FileFilter() {
public boolean accept(File file) {
return file.isDirectory();
}
};
File[] files = dir.listFiles(fileFilter);
}
}
Filters files based on the extension (what the filename ends with)
/****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one *
* or more contributor license agreements. See the NOTICE file *
* distributed with this work for additional information *
* regarding copyright ownership. The ASF licenses this file *
* to you 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. *
****************************************************************/
import java.io.File;
import java.io.FilenameFilter;
/**
* This filters files based on the extension (what the filename
* ends with). This is used in retrieving all the files of a
* particular type.
*
* Eg., to retrieve and print all <code>*.java</code> files in the current directory:
*
* <pre>
* File dir = new File(".");
* String[] files = dir.list( new ExtensionFileFilter( new String[]{"java"} ) );
* for (int i=0; i<files.length; i++)
* {
* System.out.println(files[i]);
* }
* </pre>
*
* @author Federico Barbieri <fede@apache.org>
* @author Serge Knystautas <sergek@lokitech.ru>
* @author Peter Donald
* @version CVS $Revision: 494012 $ $Date: 2007-01-08 11:23:58 +0100 (Mo, 08 Jan 2007) $
* @since 4.0
*/
public class ExtensionFileFilter
implements FilenameFilter
{
private String[] m_extensions;
public ExtensionFileFilter( final String[] extensions )
{
m_extensions = extensions;
}
public ExtensionFileFilter( final String extension )
{
m_extensions = new String[]{extension};
}
public boolean accept( final File file, final String name )
{
for( int i = 0; i < m_extensions.length; i++ )
{
if( name.endsWith( m_extensions[ i ] ) )
{
return true;
}
}
return false;
}
}
Generic File Filter
import java.io.File;
import javax.swing.filechooser.FileFilter;
public class GenericFileFilter extends FileFilter {
private String[] fileExts;
private String description;
private String extension;
public GenericFileFilter(String[] filesExtsIn, String description) {
fileExts = filesExtsIn;
this.description = description;
}
public boolean accept(File f) {
if (f.isDirectory()) {
return true;
}
extension = getExtension(f);
if (extension != null) {
for (int i = 0; i < fileExts.length; i++) {
if (check(fileExts[i]))
return true;
}
}
return false;
}
private boolean check(String in) {
return extension.equalsIgnoreCase(in);
}
public String getDescription() {
return description;
}
private String getExtension(File file) {
String filename = file.getName();
int length = filename.length();
int i = filename.lastIndexOf(".");
if (i > 0 && i < length - 1)
return filename.substring(i + 1).toLowerCase();
return null;
}
}
Inverted File Filter
/****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one *
* or more contributor license agreements. See the NOTICE file *
* distributed with this work for additional information *
* regarding copyright ownership. The ASF licenses this file *
* to you 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. *
****************************************************************/
import java.io.File;
import java.io.FilenameFilter;
/**
* This takes a <code>FilenameFilter<code> as input and inverts the selection.
* This is used in retrieving files that are not accepted by a filter.
*
* @author
* @version CVS $Revision: 494012 $ $Date: 2007-01-08 11:23:58 +0100 (Mo, 08 Jan 2007) $
* @since 4.0
*/
public class InvertedFileFilter
implements FilenameFilter
{
private final FilenameFilter m_originalFilter;
public InvertedFileFilter( final FilenameFilter originalFilter )
{
m_originalFilter = originalFilter;
}
public boolean accept( final File file, final String name )
{
return !m_originalFilter.accept( file, name );
}
}
List file with file filter
import java.io.File;
import java.io.FileFilter;
public class MainClass {
public static void main(String[] args) {
File cwd = new File(System.getProperty("user.dir"));
File[] htmlFiles = cwd.listFiles(new HTMLFileFilter());
for (int i = 0; i < htmlFiles.length; i++) {
System.out.println(htmlFiles[i]);
}
}
}
class HTMLFileFilter implements FileFilter {
public boolean accept(File pathname) {
if (pathname.getName().endsWith(".html"))
return true;
if (pathname.getName().endsWith(".htm"))
return true;
return false;
}
}
This filter accepts Files that are directories
/****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one *
* or more contributor license agreements. See the NOTICE file *
* distributed with this work for additional information *
* regarding copyright ownership. The ASF licenses this file *
* to you 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. *
****************************************************************/
import java.io.File;
import java.io.FilenameFilter;
/**
* This filter accepts <code>File</code>s that are directories.
* Eg., here is how to print out a list of the current directory"s subdirectories:
*
* <pre>
* File dir = new File(".");
* String[] files = dir.list( new DirectoryFileFilter() );
* for ( int i=0; i<files.length; i++ )
* {
* System.out.println(files[i]);
* }
* </pre>
*
* @author
* @version $Revision: 494012 $ $Date: 2007-01-08 11:23:58 +0100 (Mo, 08 Jan 2007) $
* @since 4.0
*/
public class DirectoryFileFilter
implements FilenameFilter
{
public boolean accept( final File file, final String name )
{
return new File( file, name ).isDirectory();
}
}
