import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class JButtonDemo extends JPanel implements ActionListener{
JButton b1,b2,b3;
static JLabel l1,l2;

JButtonDemo(){
l1=new JLabel("JButton舉例",JLabel.CENTER);
l2=new JLabel("",JLabel.CENTER);
b1=new JButton("歡迎");
b1.setActionCommand("welcome");
b2=new JButton("時間");
//b2.setActionCommand("time");
b3=new JButton("退出");
b1.addActionListener(this);b2.addActionListener(this);b3.addActionListener(this);
add(b1);add(b2);add(b3);}

public void actionPerformed(ActionEvent e){
	Calendar c1=Calendar.getInstance();
	if(e.getActionCommand().equals("welcome"))
	l2.setText("java歡迎您！");
	else if(e.getSource().equals(b2))
	l2.setText("今天是"+c1.get(Calendar.YEAR)+"年"+c1.get(Calendar.MONTH)+"月"+c1.get(Calendar.DATE)+"日");
	else System.exit(0);}

public static void main(String args[]){
	JFrame frame1=new JFrame();
	frame1.getContentPane().add(new JButtonDemo(),BorderLayout.SOUTH);
	frame1.getContentPane().add(l1,BorderLayout.NORTH);
	frame1.getContentPane().add(l2,BorderLayout.CENTER);
	frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	frame1.pack();frame1.setVisible(true);}}