小时钟

 
/**  
 * author zjsrustar 
 */  
//package MainPackage;   
import javax.swing.*;   
import java.awt.*;   
import java.awt.geom.*;   
import java.awt.event.*;   
import java.util.Calendar;   
import java.util.GregorianCalendar;   
/**  
 * This is the main Function of the program.  
 */  
public class Clock{   
    public static void main(String []args){   
        ClockFrame frame = new ClockFrame();   
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   
        frame.setVisible(true);   
    }   
}   
/**  
 * This class is used to define the main frame of the clock  
 */  
class ClockFrame extends JFrame{   
    //constructor function   
    public ClockFrame(){   
        setTitle("小时钟");   
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);   
        setLocation(DEFAULT_LOC_WIDTH, DEFAULT_LOC_HEIGHT);   
        ClockPanel panel = new ClockPanel();   
        add(panel);   
    }   
       
    //variables of the frame   
    private int DEFAULT_LOC_WIDTH = 300;   
    private int DEFAULT_LOC_HEIGHT = 300;   
    private int DEFAULT_WIDTH = 330;   
    private int DEFAULT_HEIGHT = 330;   
}   
/**  
 * This class is used to defind the main panel of the clock  
 */  
class ClockPanel extends JPanel{   
    public void paintComponent(Graphics g){   
        super.paintComponent(g);   
        Graphics2D g2 = (Graphics2D) g;   
           
        //get the time of the system   
        GregorianCalendar calendar = new GregorianCalendar();   
        int hour = calendar.get(Calendar.HOUR);   
        int minute = calendar.get(Calendar.MINUTE);   
        int second = calendar.get(Calendar.SECOND);   
           
        //draw the clock face   
        Ellipse2D clockFace = new Ellipse2D.Double();   
        clockFace.setFrameFromCenter(CENTER_X, CENTER_Y, CENTER_X+RADIUS, CENTER_Y+RADIUS);   
        g2.setColor(Color.BLUE);   
        g2.draw(clockFace);   
           
        //draw the clock center   
        Ellipse2D clockCenter = new Ellipse2D.Double();   
        clockCenter.setFrameFromCenter(CENTER_X, CENTER_Y, CENTER_X+INNER_RADIUS, CENTER_Y+INNER_RADIUS);   
        g2.setColor(Color.RED);   
        g2.fill(clockCenter);   
           
        //help to get the exact position of the lines   
        double lenX, lenY, posX, posY;   
           
        //draw the clock second line   
        Line2D clockSecond = new Line2D.Double();   
        double secondTime = (double) calendar.get(Calendar.SECOND);   
        lenX = SECOND_LEN*Math.sin(2*Math.PI*secondTime/60.0);   
        lenY = SECOND_LEN*Math.cos(2*Math.PI*secondTime/60.0);   
        posX = CENTER_X + lenX;   
        posY = CENTER_Y - lenY;   
        clockSecond.setLine(CENTER_X, CENTER_Y, posX, posY);   
        g2.setColor(Color.PINK);   
        g2.draw(clockSecond);   
           
        //draw the clock minute line   
        Line2D clockMinute = new Line2D.Double();   
        double minuteTime = (double) calendar.get(Calendar.MINUTE);   
        lenX = MINUTE_LEN*Math.sin(2*Math.PI*(secondTime+60*minuteTime)/3600.0);   
        lenY = MINUTE_LEN*Math.cos(2*Math.PI*(secondTime+60*minuteTime)/3600.0);   
        posX = CENTER_X + lenX;   
        posY = CENTER_Y - lenY;   
        clockMinute.setLine(CENTER_X, CENTER_Y, posX, posY);   
        g2.setColor(Color.GREEN);   
        g2.draw(clockMinute);   
           
        //draw the clock hour line   
        Line2D clockHour = new Line2D.Double();   
        double hourTime = (double) calendar.get(Calendar.HOUR);   
        lenX = HOUR_LEN*Math.sin(2*Math.PI*((secondTime+60*minuteTime+3600*hourTime)/43200.0));   
        lenY = HOUR_LEN*Math.cos(2*Math.PI*((secondTime+60*minuteTime+3600*hourTime)/43200.0));   
        posX = CENTER_X + lenX;   
        posY = CENTER_Y - lenY;   
        clockHour.setLine(CENTER_X, CENTER_Y, posX, posY);   
        g2.setColor(Color.BLUE);   
        g2.draw(clockHour);   
           
        int delay = 1000;   
        // actionListener   
        ActionListener drawClock;          
        drawClock=new ActionListener(){   
              public void actionPerformed(ActionEvent evt){   
                 repaint();   
              }   
           };   
        //create timer       
        new Timer(delay, drawClock).start();   
    }   
       
    //variables of the panel   
    private int HOUR_LEN = 50;   
    private int MINUTE_LEN = 70;   
    private int SECOND_LEN = 90;   
    private int RADIUS = 100;   
    private int INNER_RADIUS = 2;   
    private int CENTER_X = 150;   
    private int CENTER_Y = 150;   
}