Java File list(FilenameFilter filter) method example

public String[] list(FilenameFilter filter)

This method returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that were accepted by the given filter. The array will be empty if the directory is empty or if no names were accepted by the filter. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Requires Java 1.0 and up

Below is a java code demonstrates the use of list(FilenameFilter filter) method of File class. The example presented might be simple however it shows the behaviour of the list(FilenameFilter filter) method of File class. Because the list(FilenameFilter filter) method returns an array of String filtered depending on the FilenameFilter as method argument, it is imperative that the abstract pathname is a directory. As such we have put a check isDirectory() to make sure that the pathname is a directory or not before proceeding with the operation.

package com.javatutorialhq.java.examples;

import java.io.File;
import java.io.FilenameFilter;


/*
 * This example source code demonstrates the use of  
 * list(FilenameFilter filter) method of File class.
 * 
 */

public class FileListFilenameFilterExample {

	public static void main(String[] args) {

		// initialize File object
		File file = new File("C:javatutorialhqinput");

		// check if the specified pathname is directory first
		if(file.isDirectory()){
			//list specified files on the specified directory
			String[] files = file.list(new FilenameFilter() {
				
				@Override
				public boolean accept(File dir, String name) {
					boolean value;
					// return files only that begins with test
					if(name.startsWith("test")){
						value=true;
					}
					else{
						value=false;
					}
					return value;
				}
			});
			for(String s:files){
				System.out.println(s);
			}
		}
	}
}

Below is the sample output when you run the above example.

• Java File Class Tutorial
• Java Tutorial

• Oracle Java Documentation