How to Use a FileFilter in Java to List Files

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In this example we use a FileFilter to list files of a certain type. To implement the FileFilter interface we need to create an accept() method which takes a java.io.File object as parameter.
In the method we check wheter the name ends with ".txt" and if so we return true, else false.
When we have created the FileFilter we can pass it to the listFiles method of the java.io.File class which will use it to return an array of all files that the filter returned true for in its accept method.
In the example we check the C:\temp folder for files ending with the .txt extension.

package com.javadb.examples;

import java.io.File;
import java.io.FileFilter;

/**
*
* @author www.javadb.com
*/
public class FileUtil {

    public void myListFiles(String dir) {

        File directory = new File(dir);

        if (!directory.isDirectory()) {
            System.out.println("No directory provided");
            return;
        }

        File[] files = directory.listFiles(filefilter);

        for (File f : files) {
            System.out.println(f.getName());
        }
    }

    //create a FileFilter and override its accept-method
    FileFilter filefilter = new FileFilter() {

        public boolean accept(File file) {
            //if the file extension is .txt return true, else false
            if (file.getName().endsWith(".txt")) {
                return true;
            }
            return false;
        }
    };

    public static void main(String[] args) {
        FileUtil fileutil = new FileUtil();
        fileutil.myListFiles("C:\\\\temp");
    }
}

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