Recursively list all files within a directory using nio.file.DirectoryStream;

Solution 1:

Java 8 provides a nice way for that:

Files.walk(path)

This method returns Stream<Path>.

Solution 2:

Make a method which will call itself if a next element is directory

void listFiles(Path path) throws IOException {
    try (DirectoryStream<Path> stream = Files.newDirectoryStream(path)) {
        for (Path entry : stream) {
            if (Files.isDirectory(entry)) {
                listFiles(entry);
            }
            files.add(entry);
        }
    }
}

Solution 3:

Check FileVisitor, very neat.

 Path path= Paths.get("C:\\Users\\Danny\\Documents\\workspace\\Test\\bin\\SomeFiles");
 final List<Path> files=new ArrayList<>();
 try {
    Files.walkFileTree(path, new SimpleFileVisitor<Path>(){
     @Override
     public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
          if(!attrs.isDirectory()){
               files.add(file);
          }
          return FileVisitResult.CONTINUE;
      }
     });
 } catch (IOException e) {
      e.printStackTrace();
 }

Solution 4:

If you want to avoid having the function calling itself recursively and having a file list that is a member variable, you can use a stack:

private List<Path> listFiles(Path path) throws IOException {
    Deque<Path> stack = new ArrayDeque<Path>();
    final List<Path> files = new LinkedList<>();

    stack.push(path);

    while (!stack.isEmpty()) {
        DirectoryStream<Path> stream = Files.newDirectoryStream(stack.pop());
        for (Path entry : stream) {
            if (Files.isDirectory(entry)) {
                stack.push(entry);
            }
            else {
                files.add(entry);
            }
        }
        stream.close();
    }

    return files;
}

Solution 5:

This is the shortest implementation I came up with:

final List<Path> files = new ArrayList<>();
Path path = Paths.get("C:\\Users\\Danny\\Documents\\workspace\\Test\\bin\\SomeFiles");
try {
    Files.walk(path).forEach(entry -> list.add(entry));
} catch (IOException e) {
    e.printStackTrack();
}