10+

本压缩文档为《Java大学实用教程》（7-121-00959-5 电子工业出版社 2005.3） 的电子教案。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
class Win extends JFrame implements MouseListener
{  
    JLabel b[]=new JLabel[12];
    Icon iconGreen=new ImageIcon("a.gif"),
         iconRed=new ImageIcon("b.gif");
    Win()
    { 
      Container con=getContentPane();
      con.setLayout(new GridLayout(3,4));
      for(int i=0;i<b.length;i++)
        {
          b[i]=new JLabel(iconGreen);
          con.add(b[i]);
          b[i].addMouseListener(this);
          b[i].setBorder(BorderFactory.createBevelBorder(
                         BevelBorder.RAISED,Color.red,Color.white)); 
        }
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setBounds(10,10,380,300);
      setVisible(true); 
      validate();
    }
    public void mousePressed(MouseEvent e)
    { 
      JLabel label=(JLabel)e.getSource();
      label.setIcon(iconRed);
      int m=(int)(Math.random()*b.length);
      e=SwingUtilities.convertMouseEvent(label,e,b[m]);//转移鼠标事件随机转移到一个组件。
         if(e.getSource()==b[m])
           {
              b[m].setIcon(iconRed) ;
           }
    }
    public void mouseReleased(MouseEvent e)
    {
     for(int i=0;i<b.length;i++)
       {
          b[i].setIcon(iconGreen); 
       }  
    }
    public void mouseEntered(MouseEvent e)  {}
    public void mouseExited(MouseEvent e) {}
    public void mouseClicked(MouseEvent e){}
}
public class Example
{ 
    public static void main(String args[])
    { 
       Win win=new Win();
    }
}