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();
    }
}