java经典小程序,java入门100例!_

class Test{

   
public static void main(String[] args) {

       
Printer p = new Printer();

       
Thread t1 = new NumberPrinter(p);

       
Thread t2 = new LetterPrinter(p);

       
t1.start();

       
t2.start();

   
}   

}

class Printer{

   
private int index = 1;//设为1，方便计算3的倍数

   
//打印数字的构造方法，每打印两个数字，等待打印一个字母

   
public synchronized void print(int i){

       
while(index%3==0){try{wait();}catch(Exception e){}}

       
System.out.print(" " i);

       
index ;

       
notifyAll();

    }

   
//打印字母，每打印一个字母，等待打印两个数字

   
public synchronized void print(char c){

       
while(index%3!=0){try{wait();}catch(Exception e){}}

       
System.out.print(" " c);

       
index ;

       
notifyAll();

   
}   

}

//打印数字的线程

class NumberPrinter extends Thread{

   
private Printer p;

   
public NumberPrinter(Printer p){this.p = p;}

   
public void run(){

       
for(int i = 1; i<=52; i ){

           
p.print(i);

       
}

    }

}

//打印字母的线程

class LetterPrinter extends Thread{

   
private Printer p;

   
public LetterPrinter(Printer p){this.p = p;}

    public void run(){

       
for(char c='A'; c<='Z'; c ){

           
p.print(c);

       
}

    }

}