通过实例可以更好的了解java

19-例子1
public class Example19_1 
{ static Lefthand left;static Righthand right;  
  public  static void main(String args[])
  {left=new Lefthand()   ;//创建两个线程。
    right=new Righthand();
    left.start();      //线程开始运行后，Lefthand类中的run方法将被执行。
    right.start();
  }
}
class Lefthand extends Thread
{  
public void run()
 {
  for(int i=0;i<=5;i++)
   { System.out.println("i am student");
    try{sleep(500);}
    catch(InterruptedException e){}
   }
 } 
}
class Righthand extends Thread
{ 
public void run()
 { 
   for(int i=0;i<=5;i++)
   {System.out.println("i am oookkk");
    try{sleep(300);}
    catch(InterruptedException e){}
   }
 } 
}



19-例子2
import java.applet.*;import java.awt.*;
public class Example19_2 extends java.applet.Applet implements Runnable
{ Thread circleThread;
public void start()
 {
  if (circleThread ==null)
  {
    circleThread =new Thread(this);
    circleThread .start();
  }
 }
 public void run ()
 {
  while(circleThread !=null)
  {
   repaint();
   try{
     circleThread .sleep(1000);
     } 
   catch(InterruptedException e){}
  }
 }
 public void paint(Graphics g)
 {double i=Math.random();
  if(i<0.5)
  g.setColor(Color.red); 
  else
  g.setColor(Color.blue);
  g.fillOval(100,100,(int)(100*i),(int)(100*i));
 }
 public void stop()
 {
  circleThread.yield();
  circleThread =null;
 }
}  



19-例子3
import java.awt.*;
import java.awt.event.*;
public class Example19_3
{public static void main(String args[])
 {Mywin win=new Mywin();win.pack();
 }
}
class Mywin extends Frame implements Runnable
{ Button b=new Button("ok");int x=5;
  Thread bird=null;
  Mywin()
  {setBounds(100,100,120,120);setLayout(new FlowLayout());
   setVisible(true);
   add(b);b.setBackground(Color.green);
   addWindowListener(new WindowAdapter()
    {public void windowClosing(WindowEvent e)
      {System.exit(0);}} );
    bird=new Thread(this);//创建一个新的线程，窗口做目标对象，
                          //替线程bird实现接口Runnable。
    bird.start();         //在创建窗口时又开始了线程bird。
  }
 public void run()      //实现bird的操作。
 {while(true)
  { x=x+1;
    if(x>100) x=5;
    b.setBounds(40,40,x,x);
    try{bird.sleep(200);}
    catch(InterruptedException e){} 
  }
 }
}



19-例子4
import java.applet.*;import java.awt.*;
public class Example19_4 extends java.applet.Applet implements Runnable
{  int x=0;   Thread Scrollwords=null;
 public void init()
 {setBackground(Color.cyan);
  setForeground(Color.red);
  setFont(new Font("TimesRoman",Font.BOLD,18));
 }
public void start()
 {
  if (Scrollwords ==null)
  {
    Scrollwords =new Thread(this);
    Scrollwords .start();
  }
 }
 public void run ()
 {
  while(Scrollwords !=null)
  {x=x+5;
   if(x>500)
   x=0;
  repaint();
   try{
    Scrollwords .sleep(80);
     } 
   catch(InterruptedException e){}
  }
 }
 public void paint(Graphics g)
 {g.drawString("欢 迎 使 用 本 字 典",x,80);
 }
 public void stop()
 {
  Scrollwords.yield();
  Scrollwords =null;
 }
}




19-例子5
import java.applet.*;
import java.awt.*;
import java.awt.event.*;   
public class Example19_5 extends Applet implements ActionListener,Runnable
{ TextField text1,text2;
  int x=0;   Thread Scrollwords=null; 
  public void init()
  { setBackground(Color.cyan);
    setForeground(Color.red);
    setFont(new Font("TimesRoman",Font.BOLD,18));
    text1=new TextField(10);
    text2=new TextField(10);
add(new Label("输入一个英文单词："));  add(text1);
add(new Label("汉语意思：")); add(text2);
    text1.addActionListener(this);     
  }
 public void start()
 {
  if (Scrollwords ==null)
  {
    Scrollwords =new Thread(this);
    Scrollwords .start();
  }
 }
 public void run ()
 {
  while(Scrollwords !=null)
  {x=x+5;
   if(x>500)
   x=0;
  repaint();
   try{
    Scrollwords .sleep(80);
     } 
   catch(InterruptedException e){}
  }
 }
 public void paint(Graphics g)
 {g.drawString("欢 迎 使 用 本 字 典",x,120);
 }
 public void stop()
 {
  Scrollwords.yield();
  Scrollwords =null;
 }
public void actionPerformed(ActionEvent e)
  { if((e.getSource()==text1)&&(text1.getText().equals("boy")))
     { text2.setText("男孩");}
   else if ((e.getSource()==text1)&&(text1.getText().equals("girl")))
     { text2.setText("女孩");}
   else if ((e.getSource()==text1)&&(text1.getText().equals("sun")))
     { text2.setText("太阳");}
    else
     { text2.setText("没有该单词");}
  }
}



19-例子6
import java.applet.*;import java.awt.*;import java.awt.event.*;
 public class Example19_6 extends Applet implements Runnable
{ Thread left ,right; Graphics mypen; int x,y;
  public void init()
 { left=new Thread(this);right=new Thread(this);
x=10;y=10;mypen=getGraphics();
 }
 public void start()
 {left.start();right.start();
 }
 public void run()
 { while(true)
  if(Thread.currentThread()==left)
   { x=x+1;
    if(x>240) x=10;
    mypen.setColor(Color.blue);
    mypen.clearRect(10,10,300,100); 
    mypen.drawRect(10+x,10,50,50); 
    try{left.sleep(60);    }
    catch(InterruptedException e){}
   }
 else if(Thread.currentThread()==right)
   { y=y+1;
    if(y>240) y=10; mypen.setColor(Color.red); 
    mypen.clearRect(10,110,300,100); 
    mypen.drawOval(10+y,110,50,50);
    try{right.sleep(60);    }
    catch(InterruptedException e){}
   }
 }
public void stop()
  {left=null;right=null;
  }
}



19-例子7
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class Example19_7 extends Applet implements Runnable
{Thread 红色球,兰色球; Graphics redPen,bluePen;int 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+1;
   if(Thread.currentThread()==红色球) 
   {if(t>100) t=0;
      redPen.clearRect(0,0,110,400);
      redPen.fillOval(50,(int)(1.0/2*t*9.8),5,5);
      try{红色球.sleep(40);}
        catch(InterruptedException e){}
     }
     else if(Thread.currentThread()==兰色球)
      {bluePen.clearRect(120,0,900,500); 
       bluePen.fillOval(120+7*t,(int)(1.0/2*t*9.8),5,5);
        try{兰色球.sleep(40);}
        catch(InterruptedException e){}
      } 
    }   
  } 
}




19-例子8
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Example19_8 extends Applet implements ActionListener
{ Toolkit toolkit;Button button; 
  public void init()
   {  toolkit=getToolkit();//获得一个工具包对象 
      button=new  Button("确定");add(button);
      button.addActionListener(this); 
   }
  public void actionPerformed(ActionEvent e)
  {if(e.getSource()==button)
   {for(int i=0;i<=9;i++)
     {toolkit.beep();
      try {Thread.sleep(500);}      //每隔半秒钟发出嘟声
      catch(InterruptedException e1){}
     }
   }
  }
}



19-例子9
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Example19_9 extends Applet implements Runnable
{ int money=100;TextArea text1,text2;
  Thread 会计,出纳;
  public void init()
  {会计=new Thread(this); 出纳=new Thread(this);//创建两个线程:会计、出纳。
   text1=new TextArea(20,8); text2=new TextArea(20,8);
   add(text1);add(text2);
  }
  public void start()
  { 会计.start();出纳.start();                 //线程开始。
  }
  public synchronized void 存取(int number) //存取方法。
  { if(Thread.currentThread()==会计)
    { for(int i=1;i<=3;i++)  //会计使用存取方法存入90元，存入30元，稍歇一下
      {money=money+number;                    //这时出纳仍不能使用存取方法，
        try {Thread.sleep(1000);}             //因为会计还没使用完存取方法。
        catch(InterruptedException e){}
        text1.append("\n"+money);
       }
     }
    else if(Thread.currentThread()==出纳)
    {for(int i=1;i<=2;i++) //出纳使用存取方法取出30元，取出15元，稍歇一下，
     {money=money-number/2;      //这时会计仍不能使用存取方法，
      try {Thread.sleep(1000);} //因为出纳还没使用完存取方法。
      catch(InterruptedException e){}
      text2.append("\n"+money);
     }
    }
  }
 public void run()
  { if(Thread.currentThread()==会计||Thread.currentThread()==出纳)
     {for(int i=1;i<=3;i++) //从周一到周三会计和出纳都要使用帐本。
       { 存取(30);
       }
     } 
  }
}