java 简单的窗口程序之创建框架

import java.awt.*;import javax.swing.*;public class SwingG {public static void main(String[] args) {EventQueue.invokeLater(new Runnable(){public void run(){SimpleFrame frame=new SimpleFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setVisible(true);}});}}class SimpleFrame extends JFrame{private static final int d=300;private static final int h=200;public SimpleFrame(){setSize(d,h);}}