Java简易时钟程序：初学者入门示例

import java.awt.*;
import javax.swing.*;
import java.util.*;

class Clock extends JFrame 
{
 public static double PI = 3.14159265;
 Calendar now;
 int hh;
 int mm;
 int ss;
 Clock()
 {
  super("我的时钟");
  setSize(400,400);
  setVisible(true);
 }
 public void paint(Graphics g)
 {
  g.setColor(Color.WHITE);
  g.fillRoundRect(100,100,200,200,200,200);
  g.setColor(Color.BLACK);
  g.drawString("1",(int)(200-2+100*(Math.sin(30*2*PI/360))),(int)(200+10-100*(Math.cos(30*2*PI/360))));
  g.drawString("2",(int)(200-6+100*(Math.sin(30*2*2*PI/360))),(int)(200+10-100*(Math.cos(30*2*2*PI/360))));
  g.drawString("3",(int)(200-7+100*(Math.sin(30*3*2*PI/360))),(int)(200-100*(Math.cos(30*3*2*PI/360))));
  g.drawString("4",(int)(200-6+100*(Math.sin(30*4*2*PI/360))),(int)(200-100*(Math.cos(30*4*2*PI/360))));
  g.drawString("5",(int)(200-2+100*(Math.sin(30*5*2*PI/360))),(int)(200-2-100*(Math.cos(30*5*2*PI/360))));
  g.drawString("6",(int)(200+100*(Math.sin(30*6*2*PI/360))),(int)(200-100*(Math.cos(30*6*2*PI/360))));
  g.drawString("7",(int)(200+100*(Math.sin(30*7*2*PI/360))),(int)(200-100*(Math.cos(30*7*2*PI/360))));
  g.drawString("8",(int)(200+100*(Math.sin(30*8*2*PI/360))),(int)(200-100*(Math.cos(30*8*2*PI/360))));