事件3：点击一个按钮，弹出一个对话框

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

public   class  ActionThree  extends  JFrame ... {
    public static void main(String[] args) ...{
           new ActionThree();
    }
    
    
    JButton b,b1;
    public ActionThree() ...{
        super("action first");
        //JPanel p=new JPanel();
        this.setLayout(new FlowLayout());
        b=new JButton("click");
        b1=new JButton("reClick");
        this.getContentPane().add(b);
        this.getContentPane().add(b1);
    
        b.addActionListener(new action());//注册监听
        b1.addActionListener(new action());
        this.setSize(300,300);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
        class action implements ActionListener...{
            public void actionPerformed(ActionEvent e)...{
            /**//*if(e.getActionCommand().equals("click"))
                {
                    JOptionPane.showMessageDialog(ActionThree.this,"小子，你又错了，最后一次了！！");
                 //静态方法。不用声明
                }
                else
                   JOptionPane.showMessageDialog(ActionThree.this,"123456789");*/
            
            JButton jb=(JButton)e.getSource();
            if(jb==b)
                JOptionPane.showMessageDialog(ActionThree.this,"小子，你又错了，最后一次了！！");
            else
                JOptionPane.showMessageDialog(ActionThree.this,"123456789");
            
        }
        
    }    
    
}