Java: FileFilter

javax.swing.filechooser.FileFilter is used to restrict the files that are shown in a JFileChooser. By default, a file chooser shows all user files and directories in a file chooser dialog, with the exception of "hidden" files in Unix (those starting with a '.'). You may restrict the list that is shown by setting the file filter for a file chooser dialog.

Name Confusion. There are several file filtering classes and interfaces in Java, which often leads to confusion.

Setting a FileFilter

You need to create a file filter object by subclassing the javax.swing.filechooser.FileFilter class and defining the two methods accept and getDescription.

import javax.swing.*;
. . .
JFileChooser fc = new JFileChooser();
FileFilter filter = new FileFilter() {
fc.setFileFilter(FileFilter filter);

To display only specified extensions

This example displays only .html files. Note that it's very important to also allow directories (f.isDirectory()) if you want the user to be able to move around the file system.

// File :   fileutilstest/
// Purpose: Restricts JFileChooser to show only  HTML files.
// Author:  Fred Swartz
// Date:    2005-02-25


class HTMLFileFilter extends javax.swing.filechooser.FileFilter {
    public boolean accept(File f) {
        return f.isDirectory() || f.getName().toLowerCase().endsWith(".html");
    public String getDescription() {
        return ".html files";

For this to work, be sure that the file chooser looks at both files and directories.


Setting a list of user selectable file filters

In an output file dialog, the user is sometimes presented with a choices of the format to save a file. These choosable file filters can be set and examined with:

fc.addChoosableFileFilter(FileFilter filter);
filter = fc.getFileFilter();

Don't use ...

You will not use or for a file chooser dialog - they have other uses.