java实例化代码------------------监听事件

 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;

 public class ButtonTest
 {
     public static void main(String args[])
     {
         ButtonFrame frame = new ButtonFrame();
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
     }
 }

 class ButtonFrame extends JFrame
 {
     public ButtonFrame()
     {
         setTitle("Button Test");
         setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);


         ButtonPanel panel = new ButtonPanel();
         add(panel);
     }

     public static final int DEFAULT_WIDTH = 800;
     public static final int DEFAULT_HEIGHT = 500;
 }

 class ButtonPanel extends JPanel
 {
     public ButtonPanel()
     {
         //定义button
         JButton yellowButton = new JButton("yellow");
         JButton blueButton = new JButton("blue");
         JButton redButton = new JButton("red");

         //添加button到面板
         add(yellowButton);
         add(blueButton);
         add(redButton);

         //创建按钮动作
         ColorAction yellowAction = new ColorAction(Color.YELLOW);
         ColorAction blueAction = new ColorAction(Color.BLUE);
         ColorAction redAction = new ColorAction(Color.RED);

         //关联按钮与动作
         yellowButton.addActionListener(yellowAction);
         blueButton.addActionListener(blueAction);
         redButton.addActionListener(redAction);
     }

     private class ColorAction implements ActionListener
     {
         public ColorAction(Color c)
         {
             backgroundColor = c;
         }

         public void actionPerformed(ActionEvent event)
         {
             setBackground(backgroundColor);
         }

         private Color backgroundColor;
     }
 }