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How to get the content of a directory?

In this example you'll see how to read the list of files inside a directory. To get this functionality we can use the File.listFiles() method. This method return an array of File object which can be either an instance of file or directory.

package com.javacoderanch.sample.java.io;

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

public class DirectoryContentExample
{
    public static void main(String[] args)
    {
        File games = new File("D:\Games");

        // Get a list of file under the specified directory
        // above and return it as an abstract file object.
        File[] files = games.listFiles();

        // Iterates the content of games directory, print it
        // and check it whether it was a directory or a file.
        for (File file : files)
        {
            System.out.println(file + " is a " 
                    + (file.isDirectory() ? "directory" : "file"));
        }

        // Here we also get the list of file in the directory but
        // return it just as an array of String.
        String[] xfiles = games.list();
        for (String file : xfiles)
        {
            System.out.println("File = " + file);
        }

        // Now we want to list the file in the directory but
        // we just want a file with a .doc extension. To do
        // this we first create a FilenameFilter which will
        // be given to the listFiles() method to filter the
        // listing process. The rule of filtering is
        // implemented in the accept() method of the
        // FilenameFilter interface.
        FilenameFilter filter = new FilenameFilter()
        {
            public boolean accept(File dir, String name)
            {
                if (name.endsWith(".doc"))
                {
                    return true;
                }
                return false;
            }
        };

        // Give me just a .doc files in your directory.
        File[] yfiles = games.listFiles(filter);
        for (File doc : yfiles)
        {
            System.out.println("Doc file = " + doc);
        }
    }
}

Here is the result of the program:

The File[] array returned:

D:GamesAOE is a directory
D:GamesChampionship Manager 2007 is a directory
D:GamesGameHouse is a directory
D:GamesSierra is a directory
D:Gamestesting.doc is a file
D:GamesTTD is a directory

The String[] array returned.

File = AOE
File = Championship Manager 2007
File = GameHouse
File = Sierra
File = testing.doc
File = TTD

The File[] array using FilenameFilter result.

Doc file = D:Gamestesting.doc