Java I/O - 如何将文件或目录移动到其他目录

import java.io.File;

public class Main {
  public static void main(String[] argv) throws Exception {
    File file = new File("filename");
    File dir = new File("directoryname");

    boolean success = file.renameTo(new File(dir, file.getName()));
    if (!success) {
      System.out.println("File was not successfully moved");
    }
  }
}