Java/File Input Output/FilenameFilter
Содержание
- 1 Accepts a selection if it is acceptable to both of two FilenameFilters
- 2 A simple file filter for a particular file extension
- 3 Inverted File Filter
- 4 only display files that use the .html extension.
- 5 Removes the file extension from the given file name.
- 6 Returns the file extension of the given file name. The returned value will contain the dot.
- 7 This filter accepts Files that are directories
Accepts a selection if it is acceptable to both of two FilenameFilters
import java.io.File;
import java.io.FilenameFilter;
/**
* Accepts a selection if it is acceptable to both of two {@link FilenameFilter}s.
* This takes two {@link FilenameFilter}s as input.
*
* <p>Eg., to print all files beginning with <code>A</code> and ending with <code>.java</code>:</p>
*
* <pre>
* File dir = new File(".");
* String[] files = dir.list( new AndFileFilter(
* new PrefixFileFilter("A"),
* new ExtensionFileFilter(".java")
* )
* );
* 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 AndFileFilter
implements FilenameFilter
{
private final FilenameFilter m_filter1;
private final FilenameFilter m_filter2;
public AndFileFilter( final FilenameFilter filter1, final FilenameFilter filter2 )
{
m_filter1 = filter1;
m_filter2 = filter2;
}
public boolean accept( final File file, final String name )
{
return m_filter1.accept( file, name ) && m_filter2.accept( file, name );
}
}
A simple file filter for a particular file extension
//revised from prefuse
import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import javax.swing.filechooser.FileFilter;
/**
* A simple file filter for a particular file extension.
*
* @author
*/
public class SimpleFileFilter extends FileFilter {
private ArrayList exts = new ArrayList();
private String desc;
private Object data;
/**
* Create a new SimpleFileFilter.
* @param ext the file extension
* @param desc a description of the file type
*/
public SimpleFileFilter(String ext, String desc) {
addExtension(ext);
this.desc = desc;
}
/**
* Create a new SimpleFileFilter.
* @param ext the file extension
* @param desc a description of the file type
* @param data user-provided attached object
*/
public SimpleFileFilter(String ext, String desc, Object data) {
addExtension(ext);
this.desc = desc;
this.data = data;
}
/**
* Add a file extension to this file filter.
* @param ext the file extension to add
*/
public void addExtension(String ext) {
exts.add(ext.toLowerCase());
}
/**
* @see javax.swing.filechooser.FileFilter#accept(java.io.File)
*/
public boolean accept(File f) {
if ( f == null )
return false;
if ( f.isDirectory() )
return true;
String extension = getExtension(f);
if ( extension == null ) return false;
for ( Iterator iter = exts.iterator(); iter.hasNext(); ) {
String ext = (String)iter.next();
if ( ext.equalsIgnoreCase(extension) )
return true;
}
return false;
}
/**
* Returns the extension for a file or null if there is none
* @param f the input file
* @return the file extension, or null if none
*/
public static String getExtension(File f) {
return (f != null ? getExtension(f.getName()) : null);
}
/**
* Returns the extension for a file or null if there is none
* @param filename the input filename
* @return the file extension, or null if none
*/
public static String getExtension(String filename) {
int i = filename.lastIndexOf(".");
if ( i>0 && i<filename.length()-1 ) {
return filename.substring(i+1).toLowerCase();
} else {
return null;
}
}
/**
* Get a user-provided attached object.
* @return the user-provided attached object
*/
public Object getUserData() {
return data;
}
/**
* @see javax.swing.filechooser.FileFilter#getDescription()
*/
public String getDescription() {
return desc;
}
/**
* Get the first file extension associated with this filter.
* @return the first file extension associated with this filter
*/
public String getExtension() {
return (String)exts.get(0);
}
} // end of class SimpleFileFilter
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 );
}
}
only display files that use the .html extension.
import java.io.File;
import java.io.FilenameFilter;
class DirListOnly {
public static void main(String args[]) {
String dirname = "/java";
File f1 = new File(dirname);
FilenameFilter only = new OnlyExt("html");
String s[] = f1.list(only);
for (int i = 0; i < s.length; i++) {
System.out.println(s[i]);
}
}
}
class OnlyExt implements FilenameFilter {
String ext;
public OnlyExt(String ext) {
this.ext = "." + ext;
}
public boolean accept(File dir, String name) {
return name.endsWith(ext);
}
}
Removes the file extension from the given file name.
import java.net.URL;
/*
* JCommon : a free general purpose class library for the Java(tm) platform
*
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------
* IOUtils.java
* ------------
* (C)opyright 2002-2004, by Thomas Morgner and Contributors.
*
* Original Author: Thomas Morgner;
* Contributor(s): David Gilbert (for Object Refinery Limited);
*
* $Id: IOUtils.java,v 1.8 2009/01/22 08:34:58 taqua Exp $
*
* Changes
* -------
* 26-Jan-2003 : Initial version
* 23-Feb-2003 : Documentation
* 25-Feb-2003 : Fixed Checkstyle issues (DG);
* 29-Apr-2003 : Moved to jcommon
* 04-Jan-2004 : Fixed JDK 1.2.2 issues with createRelativeURL;
* added support for query strings within these urls (TM);
*/
/**
* The IOUtils provide some IO related helper methods.
*
* @author Thomas Morgner.
*/
public class Main {
/**
* Removes the file extension from the given file name.
*
* @param file the file name.
* @return the file name without the file extension.
*/
public String stripFileExtension(final String file) {
final int idx = file.lastIndexOf(".");
// handles unix hidden files and files without an extension.
if (idx < 1) {
return file;
}
return file.substring(0, idx);
}
}
Returns the file extension of the given file name. The returned value will contain the dot.
import java.net.URL;
/*
* JCommon : a free general purpose class library for the Java(tm) platform
*
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------
* IOUtils.java
* ------------
* (C)opyright 2002-2004, by Thomas Morgner and Contributors.
*
* Original Author: Thomas Morgner;
* Contributor(s): David Gilbert (for Object Refinery Limited);
*
* $Id: IOUtils.java,v 1.8 2009/01/22 08:34:58 taqua Exp $
*
* Changes
* -------
* 26-Jan-2003 : Initial version
* 23-Feb-2003 : Documentation
* 25-Feb-2003 : Fixed Checkstyle issues (DG);
* 29-Apr-2003 : Moved to jcommon
* 04-Jan-2004 : Fixed JDK 1.2.2 issues with createRelativeURL;
* added support for query strings within these urls (TM);
*/
/**
* The IOUtils provide some IO related helper methods.
*
* @author Thomas Morgner.
*/
public class Main {
/**
* Returns the file extension of the given file name.
* The returned value will contain the dot.
*
* @param file the file name.
* @return the file extension.
*/
public String getFileExtension(final String file) {
final int idx = file.lastIndexOf(".");
// handles unix hidden files and files without an extension.
if (idx < 1) {
return "";
}
return file.substring(idx);
}
}
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.
* <p>Eg., here is how to print out a list of the current directory"s subdirectories:</p>
*
* <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();
}
}
