CODEWITHSUNDEEP
javalistfilerecursion
Stanislav Bozhanov
Stanislav Bozhanov

Reputation: 41

listFiles() in Java fails to get all files

I wrote this function and it seemed okey but it fails if there are more than one folders in the current directory and no files. It enters only the first folder and does it job there and ignores the other folders. How can I fix this bug?

public static void getAllFiles(File folder, List<File> result) {
    File[] listOfFiles = folder.listFiles();
    for (int i = 0; i < listOfFiles.length; i++) {
        if (listOfFiles[i].isFile()) {
           result.add(listOfFiles[i]);
        }
        if (listOfFiles[i].isDirectory()) {
            getAllFiles(listOfFiles[i], result);
        }
    }
}

Upvotes: 4

Views: 6266

Answers (3)

Daniel Michalski
Daniel Michalski

Reputation: 563

Maybe you should try walkFileTree method from NIO.2:

public List<Path> findAllFilesInDirectory(Path pathToDir) throws IOException {
    final List<Path> pathsToFiles = new ArrayList<>();

    Files.walkFileTree(pathToDir, new SimpleFileVisitor<Path>() {
        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            if (Files.isRegularFile(file)) {
                pathsToFiles.add(file);
            }
            return FileVisitResult.CONTINUE;
        }
    });

    return pathsToFiles;
}

To using NIO.2 You have to have at least a Java 1.7 version.

Documentation:

http://docs.oracle.com/javase/tutorial/essential/io/walk.html

Tutorials:

http://www.javabeat.net/visiting-all-the-files-and-directories-for-a-directory-in-java-using-nio2/

http://www.srccodes.com/p/article/20/java-file-and-directory-operations-made-easy-in-jdk7

Upvotes: 4

MadProgrammer
MadProgrammer

Reputation: 347214

I have no issue with your code, but you might be running into issues with "symbolic links" (like "My Documents" on Windows) which, while they seem to appear as directories, Java can't resolve them and calling listXxx will return null.

Having said that, you could also try using something like...

public static void getAllFiles(File folder, List<File> result) {
    System.out.println(folder.getName());
    File[] listOfFiles = folder.listFiles(new FileFilter() {
        @Override
        public boolean accept(File pathname) {
            return pathname.isFile();
        }
    });
    if (listOfFiles != null && listOfFiles.length > 0) {
        result.addAll(Arrays.asList(listOfFiles));
    }
    File[] listOfFolders = folder.listFiles(new FileFilter() {
        @Override
        public boolean accept(File pathname) {
            return pathname.isDirectory();
        }
    });
    for (File subFolder : listOfFolders) {
        getAllFiles(subFolder, result);
    }
}

instead to list the files and directories.

I believe the new nio2 (Files and Paths API) has a fix for it...

Upvotes: 1

Abhi
Abhi

Reputation: 341

I tried it as:

public void listf(String directoryName, List<File> files){ File directory = new File(directoryName) // get all the files from a directory File[] fList = directory.listFiles(); for (File file : fList) { if (file.isFile()) { files.add(file); } else if (file.isDirectory()) { listf(file.getAbsolutePath(), files); } } }

Upvotes: 1

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