example19_5.java

里面5个JAVA小程序

import java.awt.*;import java.awt.event.*;
import java.applet.*;
public class Example19_5 extends Applet 
                  implements Runnable
{  Thread 红色球,兰色球; 
   Graphics redPen,bluePen;
   double t=0;
   public void init()
   {  红色球=new Thread(this);
      兰色球=new Thread(this);
  redPen=getGraphics();bluePen=getGraphics();
  redPen.setColor(Color.red); bluePen.setColor(Color.blue);
   }
   public void start()
   {  红色球.start();兰色球.start();
   }
   public void run()
   {  while(true)
      {  t=t+0.2;
         if(Thread.currentThread()==红色球) 
            {  if(t>20)  t=0;
               redPen.clearRect(0,0,38,300);
               redPen.fillOval(20,(int)(1.0/2*t*t*3.8),16,16);
               try{  红色球.sleep(50);
                  }
               catch(InterruptedException e){}
             }
          else if(Thread.currentThread()==兰色球)
            {  bluePen.clearRect(38,0,500,300);
               bluePen.fillOval(38+(int)(16*t),(int)(1.0/2*t*t*3.8),16,16);
               try{  兰色球.sleep(50);
                  }
               catch(InterruptedException e){}
            } 
      }   
   } 
}