How do I iterate through the files in a directory in Java?

Question

I need to get a list of all the files in a directory, including files in all the sub-directories. What is the standard way to accomplish directory iteration with Java?

Answer 1

If you are using Java 1.7, you can use java.nio.file.Files.walkFileTree(...).

For example:

public class WalkFileTreeExample {

  public static void main(String[] args) {
    Path p = Paths.get("/usr");
    FileVisitor fv = new SimpleFileVisitor() {
      @Override
      public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
          throws IOException {
        System.out.println(file);
        return FileVisitResult.CONTINUE;
      }
    };

    try {
      Files.walkFileTree(p, fv);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

}

If you are using Java 8, you can use the stream interface with java.nio.file.Files.walk(...):

public class WalkFileTreeExample {

  public static void main(String[] args) {
    try (Stream paths = Files.walk(Paths.get("/usr"))) {
      paths.forEach(System.out::println);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

}