JAVA时钟

效果图如下：

 //简单动态时钟程序，以图形和数字两种方式来显示当前时间
 import javax.swing.*;
 import java.awt.event.*;
 import java.awt.*;
 import java.util.Calendar;
 import java.util.GregorianCalendar;

 public class Clock extends JFrame implements ActionListener
 {
     int x,y,x0,y0,r,h,olds_x,olds_y,oldm_x,oldm_y,oldh_x,oldh_y,ss,mm,hh,old_m,old_h,ang;
     final double RAD = Math.PI/180;    //度数转化成弧度的比例

     //构造函数创建一个窗体
     public Clock()
     {
         super("ShuBing时钟");
         setDefaultCloseOperation(3);
         //Image image = getToolkit().getImage("clock.gif");
         //setIconImage(image);
         setSize(200,200);
         setBackground(Color.BLACK);
         setLocation(300,150);
         setResizable(false);
         show();
         int delay = 1000;
         //创造一个监听事件
         ActionListener drawClock = new ActionListener()
         {
             public void actionPerformed(ActionEvent evt)
             {
                 repaint();
             }
         };
         //创造一个时间计数器，每一秒触发一次
         new Timer(delay,drawClock).start();
     }

     //实现ActionListener接口必须实现的方法
     public void actionPerformed(ActionEvent arg0) {
     }
     //绘制图形
     public void paint(Graphics g)
     {
         Graphics2D g2D = (Graphics2D) g;
         Insets insets = getInsets();
         int L = insets.left/2, T=insets.top/2;
         h = getSize().height;
         g.setColor(Color.white);
         //画圆
         g2D.setStroke(new BasicStroke(4.0f));
         g.drawOval(L+40, T+40, h-80, h-80);
         r = h/2-40;
         x0 = 40+r-5+L;
         y0 = 40+r-5-T;
         ang = 60;
         //绘制时钟上的12个数字
         for(int i=1; i<=12; i++)
         {
             x=(int)((r+10)*Math.cos(RAD*ang)+x0);
             y=(int)((r+10)*Math.sin(RAD*ang)+y0);
             g.drawString(""+i, x, h-y);
             ang -= 30;
         }
         //获得现在时间
         Calendar now = new GregorianCalendar();
         int nowh = now.get(Calendar.HOUR_OF_DAY);
         int nowm = now.get(Calendar.MINUTE);
         int nows = now.get(Calendar.SECOND);
         String st;
         if(nowh<10) st = "0"+nowh; else st = ""+nowh;
         if(nowm<10) st += ":0"+nowm; else st += ":"+nowm;
         if(nows<10) st += ":0"+nows; else st += ":"+nows;
         //在窗体上显示时间
         g.setColor(Color.pink);
         g.fillRect(L, T, 50, 28);
         g.setColor(Color.BLUE);
         g.drawString(st,L+2,T+26);
         //计算时间与度数的关系
         ss = 90 - nows*6;
         mm=90 - nowm*6;
         hh = 90 - nowh*30-nowm/2;
         x0 = r+40+L;
         y0 = r+40+T;
         g2D.setStroke(new BasicStroke(1.2f));
         //擦除秒针
         if(olds_x>0)
         {
             g.setColor(getBackground());
             g.drawLine(x0, y0, olds_x, h-olds_y);
         }
         else
         {
             old_m = mm;
             old_h = hh;
         }
         //绘制秒针
         x=(int)(r*0.9*Math.cos(RAD*ss))+x0;
         y=(int)(r*0.9*Math.sin(RAD*ss))+y0-2*T;
         g.setColor(Color.yellow);
         g.drawLine(x0, y0, x, h-y);
         olds_x = x;
         olds_y = y;
         g2D.setStroke(new BasicStroke(2.2f));
         //擦除分针
         if(old_m != mm)
         {
             g.setColor(getBackground());
             g.drawLine(x0, y0, oldm_x, h-oldm_y);
         }
         //绘制分针
         x=(int)(r*0.7*Math.cos(RAD*mm))+x0;
         y=(int)(r*0.7*Math.sin(RAD*mm))+y0-2*T;
         g.setColor(Color.green);
         g.drawLine(x0, y0, x, h-y);
         oldm_x = x;
         oldm_y = y;
         old_m = mm;
         g2D.setStroke(new BasicStroke(3.4f));
         //擦除时针
         if(old_h != hh)
         {
             g.setColor(getBackground());
             g.drawLine(x0, y0, oldh_x, h-oldh_y);
         }
         //绘制时针
         x=(int)(r*0.5*Math.cos(RAD*hh))+x0;
         y=(int)(r*0.5*Math.sin(RAD*hh))+y0-2*T;
         g.setColor(Color.red);
         g.drawLine(x0, y0, x, h-y);
         oldh_x = x;
         oldh_y = y;
         old_h = hh;
     }
     public static void main(String[] args)
     {
         new Clock();
     }
 }