[Java] Tread.sleep() 电子表显示时期和时间

import java.awt.*;    
import java.awt.event.*;    
import javax.swing.*;    
import java.util.*;    
public class DigitalClockTest{    
         public static void main(String[] args){    
                JFrame jf = new JFrame( "Digital Clock");    
                JLabel jlblClock = new JLabel( "time");    
                
                jlblClock.setHorizontalAlignment(JLabel.CENTER); //设置Label中文件居中显示    
                jf.add(jlblClock, "Center");    
                jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    
                jf.setLocationByPlatform( true);    
                jf.pack();    
                jf.setVisible( true);    
                
                MyThread mt = new MyThread(jlblClock);    
                mt.start();    
        }    
}    
class MyThread extends Thread{    
         private JLabel clock;    
        
         //得到当前的时期和时间    
         public String getTime(){    
                Calendar c = new GregorianCalendar();    
                String time = c.get(Calendar.YEAR)+ "/"+(c.get(Calendar.MONTH)+1)+ "/"+c.get(Calendar.DATE)+ " ";    
                 int h = c.get(Calendar.HOUR_OF_DAY);    
                 int m = c.get(Calendar.MINUTE);    
                 int s = c.get(Calendar.SECOND);    
                String ph = h<10 ? "0":"";    
                String pm = m<10 ? "0":"";    
                String ps = s<10 ? "0":"";    
                time+= ph+h+ ":"+pm+m+ ":"+ps+s;    
                 return time;    
        }    
         //将日期和时间显示在lable上面并设置 1 秒刷新一次    
         public MyThread(JLabel clock){    
                 this.clock = clock;    
        }    
        @Override    
         public void run(){    
                 while( true){    
                        clock.setText( this.getTime());    
                         try{    
                                Thread.sleep(1000); //设置时间间隔为1000ms    
                        }    
                         catch(Exception e){    
                                System.out.println(e);    
                        }    
                }    
        }    
}