import java.util.Date;
import java.awt.Graphics;
public class Clock extends java.applet.Applet implements Runnable
{
	Thread clockThread;
	public void start()
	{
		if (clockThread == null)
		{
			clockThread = new Thread(this, "Clock");       //߳ʵ
			clockThread.start();                         //ִ
		}
	}
	public void run()                                   //߳
	{
		while (clockThread != null)
		{
			repaint();
			try
			{
				clockThread.sleep(1000);
			}
			catch (InterruptedException e){}
		}
	} 
	public void paint(Graphics g)
	{
		Date now = new Date();                   //ȡǰϵͳʱ
		g.drawString(now.toString(), 5, 10);
	}
	public void stop()
	{
   		clockThread.stop();                      
		clockThread = null;
	} 
}
