applet2

package zhoutong;import javax.swing.*;import java.awt.*;import java.util.Random;public class T extends JApplet implements Runnable{private Thread thread;private int cot= 10;private int x,y;int dir[][]=new int[][]{{5,5},{-5,5},{-5,-5},{5,-5}};int d=0;public void init(){Random rand = new Random();x=0;y=0;while(x<100||y<100){x = (int)(Math.random()*800);y = (int)(Math.random()*800);}thread = new Thread(this);thread.start();}public void run(){while(true){repaint();try{thread.sleep(10);}catch(Exception e){System.out.println("system error");}}}public void paint(Graphics g){super.paint(g);g.setColor(Color.red);//gg.getGraphics().setColor(Color.red);//g.drawRect(100,100 , 600, 600);g.fillRect(100, 100, 700, 600);g.setColor(Color.blue);//g.drawOval( x, y, 30, 30);g.fillOval(x, y, 30, 30);if(x<100||y<100||x>780||y>680){if(d==0)d=1;else if(d==1)d=2;else if(d==2)d=3;else d=0;}x=x+dir[d][0];y=y+dir[d][1];Image ibuffer = createImage(this.getSize().width,this.getSize().height);Graphics gbuffer = ibuffer.getGraphics();}}