Java Swing - 如何使用WindowListener创建JDialog

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JDialog;

public class Main extends JDialog {

  public Main() {
    setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);
    addWindowListener(new WindowAdapter() {
      @Override
      public void windowClosing(WindowEvent e) {
        System.out.println("closing...");
      }
    });
  }

  public static void main(String[] args) {
    Main m = new Main();
    m.setVisible(true);
  }
}