具体内容如下

package pers.javacode.lzw.ballgame;import java.awt.Graphics;import java.awt.Image;import java.awt.Toolkit;import javax.swing.JFrame;public class BallGame extends JFrame { //加载图片 Image ball=Toolkit.getDefaultToolkit().getImage("images/ball.png"); Image desk=Toolkit.getDefaultToolkit().getImage("images/desk.jpg");  public void frameLunch() { this.setSize(856,500); this.setLocation(50,50); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setVisible(true); while(true) { repaint(); try { Thread.sleep(40); } catch (InterruptedException e) {  e.printStackTrace(); } }  } double x=100; double y=100; double degree=3.14/4;//对应的是60度 public void paint(Graphics g) {  g.drawImage(desk,0,0,null); g.drawImage(ball,(int)x,(int)y,null); //创建动态的小球滚动的状态 x = (x+ 10*Math.cos(degree));  y = y +10*Math.sin(degree);     //碰到上下边界  if(y>500-40-30||y<40+40){//500是窗口高度；40是桌子边框，30是球直径；最后一个40是标题栏的高度  degree = -degree;  }    //碰到左右边界  if(x<40||x>856-40-30){  degree = 3.14 - degree;  }   } public static void main(String[] args) { BallGame ba=new BallGame(); ba.setTitle("Ball Game"); ba.frameLunch(); } }