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

class Demo extends JFrame implements Runnable
{
    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 hh:mm:ss");
    private JLabel lab = new JLabel("");
    public Demo()
    {
        this.getContentPane().add(lab);
        lab.setForeground(Color.RED);
        lab.setFont(new Font("黑体",1,20));
        lab.setHorizontalAlignment(JLabel.CENTER);
        this.setSize(300,150);
        this.setLocationRelativeTo(null);
        this.setVisible(true);
        Thread t = new Thread(this);
        t.start();
    }
    
    public static void main(String[]args)
    {
        new Demo();
    }
    
    public void run()
    {
        while(true)
        {
            Date d = Calendar.getInstance().getTime();
            lab.setText(sdf.format(d));
            try 
            {
                Thread.currentThread().sleep(10);
            }
            catch (Exception ex)
            {
                
            }
        }
        
    }
}

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



/*class c13_1 extends Thread {
   int pauseTime;
   String name;
   int year,month,date,hour,minute,second;
   public c13_1(int hTime, String hStr)
 {
     pauseTime = hTime;
     name = hStr;
   }
   public void run() {
      Calendar now;
//System.out.println("ddddddddddddd");
      for(int i=1;i<500;i++){
         try {
            now=Calendar.getInstance();         //取系统时间
            year=now.get(Calendar.YEAR);        //取年值
            month=now.get(Calendar.MONTH)+1;    //取月值
            date=now.get(Calendar.DATE);        //取日期值
            hour=now.get(Calendar.HOUR_OF_DAY); //取小时值
            minute=now.get(Calendar.MINUTE);    //取分值
            second=now.get(Calendar.SECOND);    //取秒值
            label.setText(" "+year+" 年"+month+"月 "+date+"日"+hour+"小时"+minute+"分"+second+"秒" );
            Thread.sleep(pauseTime);
         }
catch(Exception e)
  {
           System.out.println("线程错误："+e);
       }
}
  }

}*/


public class c13_5
{
    public static void main(String args [] )
    {
        box box=new box();
        box.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        box.setVisible(true);
    }
}

class box extends JFrame
{
    JLabel label;
        public box()
         {
             Container cp=getContentPane();
             JButton bu1=new JButton("dd");
             cp.setLayout(new BorderLayout(10,10));
             setSize(950,700);
             final c13_1 timer = new c13_1(1000,"a");
             label=new JLabel();
             cp.setLayout(new GridLayout(2,1));
             cp.add(label);
             cp.add(bu1);
             timer.start();
             /*bu1.addActionListener(new ActionListener()
             {
                 public void actionPerformed(ActionEvent e)
                 {
             label.setText(" "+timer.year+" 年"+timer.month+"月 "+timer.date+"日"+timer.hour+"小时"+timer.minute+"分"+timer.second+"秒" );
         }
     });*/
         }
         class c13_1 extends Thread {
   int pauseTime;
   String name;
   int year,month,date,hour,minute,second;
   public c13_1(int hTime, String hStr)
 {
     pauseTime = hTime;
     name = hStr;
   }
   public void run() {
      Calendar now;
//System.out.println("ddddddddddddd");
      for(int i=1;i<500;i++){
         try {
            now=Calendar.getInstance();         //取系统时间
            year=now.get(Calendar.YEAR);        //取年值
            month=now.get(Calendar.MONTH)+1;    //取月值
            date=now.get(Calendar.DATE);        //取日期值
            hour=now.get(Calendar.HOUR_OF_DAY); //取小时值
            minute=now.get(Calendar.MINUTE);    //取分值
            second=now.get(Calendar.SECOND);    //取秒值
            label.setText(" "+year+" 年"+month+"月 "+date+"日"+hour+"小时"+minute+"分"+second+"秒" );
            Thread.sleep(pauseTime);
         }
catch(Exception e)
  {
           System.out.println("线程错误："+e);
       }
}
  }

}
     }

这是按照你的程序改的  你看一下吧  我把c13_1类作为了box类的内部类 便于属性的调用，如果按你的要求那button按钮添加上应该毫无意义  没必要给Button加上监听的~~所以我给注释掉了~~
如果要是纯粹只是实现这个功能的话还是按2楼朋友的那个方法实现~~~