Thread를 이용한 디지털 시계

import java.awt.Font;

import java.util.Calendar;

import javax.swing.JFrame;

import javax.swing.JLabel;

public class ClockEx extends JFrame{

JLabel timeLbl = new JLabel();

Font fnt = new Font("Serif", Font.BOLD, 100);

public ClockEx(){

add(timeLbl, "Center");

timeLbl.setFont(fnt);

setTime();

pack();

setVisible(true);

while(true){

try{

Thread.sleep(1000);

}catch(Exception e){}

setTime();

}

}

public void setTime(){

Calendar cal = Calendar.getInstance();

int hour = cal.get(Calendar.HOUR_OF_DAY);

int minute = cal.get(Calendar.MINUTE);

int second = cal.get(Calendar.SECOND);

String timeStr = "";

if(hour<10){

timeStr="0"+hour+":";

}else{

timeStr=hour+":";

}

if(minute<10){

timeStr+="0"+minute+":";

}else{

timeStr+=minute+":";

}

if(second<10){

timeStr+="0"+second;

}else{

timeStr+=second;

}

timeLbl.setText(timeStr);

}

public static void main(String[] args) {

new ClockEx();

}

}