运用多线程的信号灯法进行边加边计算！代码如下

public class JieChen {

public static void main(String args[]){

Sum sum = new Sum();

new Play(sum).start();

new Add(sum).start();

}

}

class Play extends Thread{

Sum sum;

public Play(Sum sum){

this.sum=sum;

}

@Override

public void run() {

for (int i = 1; i <= 20; i++) {

this.sum.s*=i;

this.sum.count++;

this.sum.play(sum.voe);

}

}

}

class Add extends Thread{

Sum sum;

public Add(Sum sum){

this.sum=sum;

}

@Override

public void run() {

for (int i = 1; i <= 20; i++) {

sum.add();

this.sum.sa+=this.sum.s;

}

}

}

class Sum{

int s=1;

int count=0;

long sa=1;

String voe;

boolean flag = true;

public synchronized void play(String voe){

if(!flag){

try{

this.wait();

}catch (InterruptedException e){

e.printStackTrace();

}

}

System.out.println("计算阶乘"+count+"!");

this.notifyAll();

this.voe=voe;

this.flag=!this.flag;

}

public synchronized void add(){

if(flag){

try{

this.wait();

}catch (InterruptedException e){

e.printStackTrace();

}

}

System.out.println("加上阶乘结果为"+sa);

this.notifyAll();

this.flag=!this.flag;

}

}

运行结果图