程序代码：

import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;

public class ball extends Canvas implements MouseListener,MouseMotionListener,ActionListener{
    private Timer time=new Timer(24,this);
    private int mouseX,mouseY;

    private int bb[][]={  //两点成一线定义墙，横竖斜都行.
            {20,0,285,0},
            {315,0,580,0},
            {600,20,600,380},
            {285,400,20,400},
            {580,400,315,400},
            {100,380,0,20}
        };

    private double MoChaLi=0.99;

    private double cc[][]={ //定义小球，第一个为母球.
            {140,340,3,0,0},//(x,y,color,弧度，力度);
            {40,40,0,0,0},
            {240,140,1,0,0},
            {340,240,2,0,0},
            {440,340,0,0,0}

        };

    private Color color[]={new Color(0x328aef),new Color(0x0f3a00),new Color(0xf32ae1),new Color(0xffffff)};
    private int xx[]={-20,-20};

    ball(){
        addMouseListener(this);
        addMouseMotionListener(this);
    }

    public void paint(Graphics g){

        g.setColor(new Color(0x3f32e3));
        for(int b[] : bb){
            g.drawLine(b[0],b[1],b[2],b[3]);
        }
        for(double b[] : cc){
                g.setColor(color[(int)b[2]]);
                g.fillOval((int)b[0],(int)b[1],20,20);

        }
        g.setColor(new Color(0xffffff));
        g.drawOval(xx[0],xx[1],20,20);

        if(xx[0]!=-20 && xx[1]!=-20){
            g.drawLine( (int) cc[0][0] + 10, (int) cc[0][1]+10 , xx[0] + 10 , xx[1] + 10 );
        }
    }

    public void mouseClicked(MouseEvent e){}


    public void mousePressed(MouseEvent e){
        if(!time.isRunning()){
            int zx=xx[0]- (int) cc[0][0];
            int zy=xx[1]- (int) cc[0][1];
            cc[0][3]=Math.atan2(zy,zx);
            cc[0][4]=10;
            clearMouse();
            time.start();
        }
    }


    public void mouseReleased(MouseEvent e){

    }


    public void mouseEntered(MouseEvent e){}

    public void mouseExited(MouseEvent e){
        clearMouse();
        repaint();    

    }

    public void mouseDragged(MouseEvent e){}

    public void mouseMoved(MouseEvent e){
        mouseX=e.getX();
        mouseY=e.getY();
        if(!time.isRunning()){
            xx[0]=mouseX-10;
            xx[1]=mouseY-10;
            repaint();
        }
    }

    private void clearMouse(){
        xx[0]=-20;
        xx[1]=-20;    
    }

    public void actionPerformed(ActionEvent e){
        boolean t=true;

        for(double b[] : cc){
            if(b[4]!=0){
                b[0]+=b[4]*Math.cos(b[3]);
                b[1]+=b[4]*Math.sin(b[3]);
                b[4]*=MoChaLi;
                b[4]=(b[4]<0.5)?0:b[4];
                t=false;
            }
        }

        if(t){
            time.stop();
            xx[0]=mouseX-10;
            xx[1]=mouseY-10;
        }else{
            double b1,b2;

            //撞墙测试开始
            for(double b[] : cc){
                for(int i[] : bb){
                    double a1=Math.sqrt( (i[0]-i[2]) * (i[0]-i[2]) + (i[1]-i[3]) * (i[1]-i[3]) );
                    double a2=Math.sqrt( (i[0]-b[0]-10) * (i[0]-b[0]-10) + (i[1]-b[1]-10) * (i[1]-b[1]-

10) );
                    double a3=Math.sqrt( (i[2]-b[0]-10) * (i[2]-b[0]-10) + (i[3]-b[1]-10) * (i[3]-b[1]-

10) );

                    double a31=Math.acos( (a2*a2+a1*a1-a3*a3)/2/a2/a1 )*180/Math.PI;
                    double a21=Math.acos( (a3*a3+a1*a1-a2*a2)/2/a3/a1 )*180/Math.PI;

                    if(a21<=90 && a31<=90){
                        double oo=0;
                        double q1=a3*Math.cos(a21*Math.PI/180);
                        double q2=a3*Math.sin(a21*Math.PI/180);
                        double w1=a2*Math.cos(a31*Math.PI/180);
                        double w2=a2*Math.sin(a31*Math.PI/180);
                        
                        if(q1<w1+1 && q1>w1-1){
                            oo=q1;
                        }else{oo=q2;}
                        if(Math.abs(oo)<11){
b[3]=(360-b[3]*180/Math.PI+2*(Math.atan2(i[1]-i[3],i[0]-i[2])*180/Math.PI))*Math.PI/180;
                        }
                    }
                }
            }
            //碰撞测试开始
        double li,vx,vy,vx1,vy1,vx2,vy2,ox,oy,vv;
            for(int i=0;i<cc.length-1;i++){
                for(int y=i+1;y<cc.length;y++){
                    vx=cc[i][0]-cc[y][0];
                    vy=cc[i][1]-cc[y][1];
                    li=Math.sqrt(vx*vx+vy*vy);
                    if(li<21){
                        vv=Math.atan2(vy,vx);
                        vx1=cc[i][4]*Math.cos(cc[i][3]);
                        vy1=cc[i][4]*Math.sin(cc[i][3]);
                        vx2=cc[y][4]*Math.cos(cc[y][3]);
                        vy2=cc[y][4]*Math.sin(cc[y][3]);

                        ox=Math.cos(vv)*vx1+Math.sin(vv)*vy1;
                        oy=Math.cos(vv)*vy1-Math.sin(vv)*vx1;
                        vx1=ox;
                        vy1=oy;

                        ox=Math.cos(vv)*vx2+Math.sin(vv)*vy2;
                        oy=Math.cos(vv)*vy2-Math.sin(vv)*vx2;
                        vx2=vx1;
                        vy2=oy;
                        
                        vx1=ox;

                        ox=Math.cos(vv)*vx1-Math.sin(vv)*vy1;
                        oy=Math.cos(vv)*vy1+Math.sin(vv)*vx1;                        

                    vx1=ox;
                        vy1=oy;
                        ox=Math.cos(vv)*vx2-Math.sin(vv)*vy2;
                        oy=Math.cos(vv)*vy2+Math.sin(vv)*vx2;    
                        vx2=ox;
                        vy2=oy;

                        cc[i][4]=Math.sqrt(vx1*vx1+vy1*vy1);
                        cc[i][3]=Math.atan2(vy1,vx1);

                        cc[y][4]=Math.sqrt(vx2*vx2+vy2*vy2);
                        cc[y][3]=Math.atan2(vy2,vx2);
                        
                    }

                }

            }
        }
        if(cc[0][0]<-10 || cc[0][0]>610 || cc[0][1]<-10 || cc[0][1]>410){
            cc[0][0]=100;
            cc[0][1]=100;
            cc[0][3]=0;
            cc[0][4]=0;
        }        
        repaint();
    }

}