Java, Simple Digital Clock 만들기 (Jar 파일)

 

import javax.swing.*;  
  
import java.awt.*;  
  
import java.util.Date;  
  
public class SimpleDigitalClock extends JPanel  
{  
JFrame frame;  
  
int currentHour;  
int currentMinute;  
int currentSecond;  
  
//Font that will be use to show digital clock  
Font myFont=new Font("Tahoma",Font.BOLD+Font.ITALIC,20);  
  
//Color that will be use to show digital clock  
Color myColor=new Color(255,0,0);  
  
//Font metrics that will use to store font informations  
//For example, width of a character  
FontMetrics fm;  
  
public SimpleDigitalClock()  
{  
//Create a window using JFrame with title ( Simple Digital Clock )  
frame=new JFrame("Simple Digital Clock");  
  
//add(this) mean add created panel into JFrame  
//Which panel ?  
//See line 81 and 7 (I hope you understand it)  
frame.add(this);  
  
//Set default close operation for JFrame  
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
  
//Set JFrame size  
frame.setSize(270,70);  
  
//Make JFrame locate at center  
frame.setLocationRelativeTo(null);  
  
//Make JFrame visible  
frame.setVisible(true);  
  
/* 
 *Loop that will make sure panel show current time 
 *like current second, current minute and current hour. 
 */  
while(true)  
{  
 //It will do all code in method paint(See line 67)  
 repaint();  
  
 try  
 {  
  Thread.sleep(900);  
 }  
 catch(Exception exception)  
 {  
  exception.printStackTrace();  
 }  
}  
}  
  
public void paint(Graphics g)  
{  
super.paint(g);  
  
/* 
 *Create  current Date object. It means it store information 
 *about current hour, minute and second. 
 */  
Date myDate=new Date();  
  
currentHour=myDate.getHours();  
currentMinute=myDate.getMinutes();  
currentSecond=myDate.getSeconds();  
  
//Set font that will use to draw digital number  
g.setFont(myFont);  
  
//Information about distance between number in digital clock  
fm=g.getFontMetrics();  
int hourXCoordinate=20;  
int minuteXCoordinate=hourXCoordinate+(fm.getMaxAdvance()*2);  
int secondXCoordinate=hourXCoordinate+(fm.getMaxAdvance()*4);  
  
//Set color that will use to draw digital number  
g.setColor(myColor);  
  
//Draw hour, draw (:) between number, draw minute and draw second.  
g.drawString(Integer.toString(currentHour),hourXCoordinate,20);  
g.drawString(":",(hourXCoordinate+minuteXCoordinate)/2,20);  
g.drawString(Integer.toString(currentMinute),minuteXCoordinate,20);  
g.drawString(":",(secondXCoordinate+minuteXCoordinate)/2,20);  
g.drawString(Integer.toString(currentSecond),secondXCoordinate,20);  
}  
  
public static void main(String[]args)  
{  
SimpleDigitalClock sdc=new SimpleDigitalClock();  
}  
}  

2) Manifest 파일을 만든다.

Manifest-Version: 1.0 
Main-Class: SimpleDigitalClock

3) Batch File을 만든다.

@echo off
javac SimpleDigitalClock.java
jar cvfm SimpleDigitalClock.jar m.txt SimpleDigitalClock.class 
start javaw -jar SimpleDigitalClock.jar

pause

Run the program, it will show screen as follows.