Java File listFiles(FileFilter filter) method with examples

1. Introduction

The listFiles(FileFilter filter) method returns an array of File objects that represent the files and directories that satisfy specified FileFilter.

2. Method signature

public File[] listFiles(FileFilter filter)

Parameters:

FileFilter filter - a file filter

Returns

File[] - an array of File objects that represent files and directories that satisfy the specified filter.

Throws

SecurityException - when we do not have access to the file or directory

3. Examples

3.1. Code snippet that prints only files (!file.isDirectory()) with the .txt extension (file.getName().endsWith(".txt"))

package com.frontbackend.java.io;

import java.io.File;
import java.io.FileFilter;
import java.io.FilenameFilter;
import java.util.Arrays;

public class FrontBackend {

    public static void main(String args[]) {

        try {
            File tmp = new File("/tmp/ttt");
            FileFilter fileFilter = file -> !file.isDirectory() && file.getName()
                                                                       .endsWith(".txt");

            File[] list = tmp.listFiles(fileFilter);

            if (list != null) {
                Arrays.stream(list)
                      .forEach(file -> {
                          System.out.println(file.getPath() + " " + (file.isDirectory() ? "dir" : "file"));
                      });
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The output:

/tmp/ttt/dest.txt file
/tmp/ttt/test.txt file

4. Conclusion

In this article, we presented the listFiles(FileFilter filter) method that could be used to filter files and directories from the specified path in the filesystem using FileFilter object.