Iterate through all files in Java

Question

I want to make my program print huge list of all files that I have on my computer. My problem is that it only prints files from first folder of the first hard-drive, when I want it to print all files located on my computer. Any ideas what am I doing wrong here? Thanks.

Here is code I use:

Main:

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;

public class Main {

    public static void main(String[] args) {
        ArrayList<File> roots = new ArrayList();
        roots.addAll(Arrays.asList(File.listRoots()));


        for (File file : roots) {
            new Searcher(file.toString().replace('\\', '/')).search();
        }
    }
}

and Searcher class:

import java.io.File;

public class Searcher {

    private String root;

    public Searcher(String root) {
        this.root = root;
    }

    public void search() {
        System.out.println(root);
        File folder = new File(root);
        File[] listOfFiles = folder.listFiles();
        for (File file : listOfFiles) {
            String path = file.getPath().replace('\\', '/');
            System.out.println(path);
            if (!path.contains(".")) {
                new Searcher(path + "/").search();
            }
        }
    }
}

Solution 1

I just tried this and it worked for me. I did have to add one null check and changed the directory evaluation method though:

package test;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;

public class Searcher {
    public static void main(String[] args) {
        ArrayList<File> roots = new ArrayList<File>();
        roots.addAll(Arrays.asList(File.listRoots()));


        for (File file : roots) {
            new Searcher(file.toString().replace('\\', '/')).search();
        }
    }

    private String root;

    public Searcher(String root) {
        this.root = root;
    }

    public void search() {
        System.out.println(root);
        File folder = new File(root);
        File[] listOfFiles = folder.listFiles();
        if(listOfFiles == null) return;  // Added condition check
        for (File file : listOfFiles) {
            String path = file.getPath().replace('\\', '/');
            System.out.println(path);
            if (file.isDirectory()) {
                new Searcher(path + "/").search();
            }
        }
    }
}

Solution 2

You should update your search method like this:

public void search() {
        System.out.println(root);
        File folder = new File(root);
        File[] listOfFiles = folder.listFiles();
        for (File file : listOfFiles) {
            String path = file.getPath().replace('\\', '/');
            System.out.println(path);
            if (file.isDirectory()) {
                new Searcher(path + "/").search();
            }
        }
    }

Solution 3

If Java 7 is an option, look into the walkFileTree() method. It will allow you to visit all files and directories in a tree, which you can start from the root of your drive. Just implement a basic FileVisitor to process the file attributes for each Path. You can get started here.

Solution 4

If you're using Java SE 7, use the new file API:

http://docs.oracle.com/javase/7/docs/api/java/nio/file/FileVisitor.html

http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#walkFileTree%28java.nio.file.Path,%20java.util.Set,%20int,%20java.nio.file.FileVisitor%29

http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#walkFileTree%28java.nio.file.Path,%20java.nio.file.FileVisitor%29

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Comments

[rajah9]

you might want to update your first hyperlink... There is no walkFileTree() method on the Files page. And thank you for providing this Java 7 option.