class Clock extends Label implements Runnable
{
  //定义Thread类型的clocker域
  public Thread clocker=null;
  public Clock()
  {
    
    //初始化时，把label设置为当前系统时间
    //调用toString方法转化为String类型
    setText(new Date().toString());
  }
  //控制线程的启动
  public void start()
  {
    if(clocker==null)
    {
      //clocker通过Thread类构造方法得到的对象进行初始化，并将Clock类的当前对象作为参数
      clocker=new Thread(this);
      clocker.start();
    }

  }
  //控制线程的停止
  public void stop()
  {
    clocker=null;
  }
  //实现Runnable接口中的run（）方法
  public void run()
  {
    Thread currentThread=Thread.currentThread();
    //判断clocker是否是当前运行的线程
    while(clocker==currentThread)
    {
            setText(new Date().toString());
            try
           {   //休眠1s钟
               clocker.sleep(1000);
      }
      catch (InterruptedException ie)
      {
        System.out.println(\"Thread error:\"+ie);
      }
    }
  
  }

}

public class ClockFrame extends Frame implements ActionListener
{
  private Button start=new Button(\"Start\");
  private Button stop=new Button(\"Stop\");
  private Clock c=new Clock();
  public ClockFrame()
  {
    super(\"电子时钟\");
    //设置窗体使用流式布局
    setLayout(new FlowLayout());
    //添加按钮并且为其注册监听器
    add(start);
    start.addActionListener(this);
    add(stop);
    stop.addActionListener(this);
    //使用继承WindowAdapter的匿名内部类来实现窗口的关闭
    addWindowListener(new WindowAdapter()
    {
      public void windowClosing(WindowEvent we)
      {System.exit(0);}
    });
    add(c);
    //使构件在窗口中得到合理的安排。
    pack();
    setVisible(true);


  }
  //通过调用Clock对象中的方法，实现对事件的响应。
  public void actionPerformed(ActionEvent ae)
  {
    if(ae.getSource()==start)
    {
      c.start();
    }
    else
      if(ae.getSource()==stop)
      c.stop();

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

import java.awt.*;
import java.awt.event.*;
import java.util.Date;

import java.awt.*;  
import javax.swing.*;  
import java.util.Date;  
 
/*TimeDemo.java 
 * @src 
public class TimeDemo extends JFrame implements Runnable {  
 
  Thread clock;  
    
  public static void main(String[] args) {  
  TimeDemo td =new TimeDemo();  
  td.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //点击可见窗口右上角的红叉关闭  
   }  
    
  public TimeDemo(){  
   super(\"雪地漫步---java多线程数字时钟\"); //继承父类构造方法，这里相当于Font(\"雪地漫步---java多线程数字时钟\");  
setTitle(\"kk\");  //这个则是子类的  
   this.setFont(new Font(\"Times New Roman\",Font.BOLD,60));  //设置字体大小  
   this.go();    //自定义go方法,用于以后开启线程  
   setBounds(400,300,300,100);  
   this.setVisible(true);  
  }  
 
   public void go(){  
  stop();  
   if(clock==null){  
  //线程执行的主题作为Thread类构造方法的参数。  
   clock=new Thread(this);  
   clock.start();     //开启线程,实现run方法  
  }  
}  
 
  public void run() {  
    while(true)   //让线程一直进行  
  {  
//repain()方法是来控制Graphics类的paint()方法的，repain()方法执行一次，即让paint()方法执行一次  
      repaint();   
     try{  
      Thread.sleep(1000);   //参数是毫秒,1秒即1000毫秒  
     }catch(InterruptedException e){}  
    }  
   }  
 
  public void stop(){  
   clock=null;  
  }  
 
  public void paint(Graphics g){  
   String s=\"\";  
   Date now=new Date();  
   int hour=now.getHours();                       
   int minute=now.getMinutes();  
   int second=now.getSeconds();  
   s=hour+\":\"+minute+\":\"+second;  
   g.setColor(Color.green);  
   Dimension dim=getSize();  
   g.fillRect(0, 0, dim.width, dim.height);  
   g.setColor(Color.red);  
   g.drawString(s, 20, 80);  
  }  
} 

import java.awt.BorderLayout;
 import java.awt.Canvas;
 import java.awt.Color;
 import java.awt.Font;
 import java.awt.Graphics;
 import java.sql.Date;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import javax.swing.JFrame;
 import javax.swing.JPanel;
 class Clock extends Canvas implements Runnable{

   /*
   http://ohgrateboy.blog.163.com我的博客
   */

   private static final long serialVersionUID = 3660124045489727166L;
   Thread t;
   JFrame frame=new JFrame();
   JPanel conPane;
   String time;
   int i=0;
   Date timer;
   public Clock(){
     conPane=(JPanel)frame.getContentPane();
     conPane.setLayout(new BorderLayout());
     conPane.setSize(280,40);
     conPane.setBackground(Color.white);
     conPane.add(this,BorderLayout.CENTER);
     t=new Thread(this);        //实例化线
    t.start();    //调用线程
    
     frame.setVisible(true);
     frame.setSize(300, 150);
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   }

   public void run(){

     while(true){

     try{

       Thread.sleep(1000);          //休眠1秒钟

    }catch(InterruptedException e){

       System.out.println(\"异常\");
     }
     this.repaint(100);

   }

   }

   public void paint(Graphics g){

     Font f=new Font(\"宋体\",Font.BOLD,16);

     SimpleDateFormat SDF=new SimpleDateFormat(\"yyyy\'年\'MM\'月\'dd\'日\'HH:mm:ss\");//格式化时间显示类型
    Calendar now=Calendar.getInstance();

     time=SDF.format(now.getTime());    //得到当前日期和时间
    g.setFont(f);

     g.setColor(Color.orange);

     g.drawString(time,45,25);

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

 }