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

//數(shù)字時鐘
public class ClockDemo extends JFrame implements Runnable{
	Thread clock;	
	
	public ClockDemo(){
		super("數(shù)字時鐘");	//調(diào)用父類構(gòu)造函數(shù)	
		setFont(new Font("Times New Roman",Font.BOLD,60));	//設(shè)置時鐘的顯示字體
		start(); //開始進程
		setSize(280,100);  //設(shè)置窗口尺寸
		setVisible(true);  //窗口可視
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  //關(guān)閉窗口時退出程序
	}
	
	public void start(){ //開始進程
		if (clock==null){ //如果進程為空值
			clock=new Thread(this); //實例化進程
			clock.start(); //開始進程
		}
	}
	
	public void run(){  //運行進程
		while (clock!=null){ 
			repaint(); //調(diào)用paint方法重繪界面
			try{
				Thread.sleep(1000);  //線程暫停一秒(1000毫秒)
			}
			catch (InterruptedException ex){
				ex.printStackTrace();  //輸出出錯信息
			}
		}	
	}
	
	public void stop(){  //停止進程
		clock=null;
	}
	
	public void paint(Graphics g){  //重載組件的paint方法
		Graphics2D g2=(Graphics2D)g;  //得到Graphics2D對象
		Calendar now=new GregorianCalendar(); //實例化日歷對象
		String timeInfo=""; //輸出信息
		int hour=now.get(Calendar.HOUR_OF_DAY); //得到小時數(shù)
		int minute=now.get(Calendar.MINUTE);   //得到分數(shù)
		int second=now.get(Calendar.SECOND);  //得到秒數(shù)
		
		if (hour<=9) 
			timeInfo+="0"+hour+":"; //格式化輸出
		else 
			timeInfo+=hour+":";
		if (minute<=9)
			timeInfo+="0"+minute+":";
		else
			timeInfo+=minute+":";
		if (second<=9)
			timeInfo+="0"+second;
		else
			timeInfo+=second;

		g.setColor(Color.white);  //設(shè)置當(dāng)前顏色為白色
		Dimension dim=getSize();  //得到窗口尺寸
		g.fillRect(0,0,dim.width,dim.height);  //填充背景色為白色
		g.setColor(Color.orange);  //設(shè)置當(dāng)前顏色為橙色
		g.drawString(timeInfo,20,80);  //顯示時間字符串
	}

	public static void main(String[] args){
		new ClockDemo();
	}
}