在java中，如何使swing的窗口显示在屏幕正中间

import java.awt.*;import javax.swing.*;public class ShowCenter extends JFrame { public static void main(String[] args) { final ShowCenter window = new ShowCenter(); SwingUtilities.invokeLater(new Runnable() { public void run() { window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.setSize(300, 100); //The following code ensure the window shown on the center of screen. Dimension dim = Toolkit.getDefaultToolkit().getScreenSize(); window.setLocation((dim.width - window.getWidth()) / 2, (dim.height - window.getHeight()) / 2); window.setVisible(true); } }); }}