java阻塞主线程的实现

1.声明计数器线程个数：

CountDownLatch latch= new CountDownLatch(2);

2.线程启动带参数latch:

Worker
worker1= new Worker("zhang
san" , 5000,
latch);

3.线程启动,主线程阻塞：

worker1.start();

latch.await();

4.线程run()方法中计数器技术开始：

public void run(){

System. out.println("Worker
" +workerName +"
do work begin at "+sdf.format( new Date()));

doWork(); //工作了

latch.countDown();//工人完成工作，计数器减一

}

5.整体代码Test：

package tets;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.concurrent.CountDownLatch;

public class CountDownLatchTest {

final static SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd
HH:mm:ss" );

public static void main(String[] args) throws InterruptedException
{

CountDownLatch latch= new CountDownLatch(2);//两个工人的协作

Worker worker1= new Worker("zhang
san" , 5000,
latch);

Worker worker2= new Worker("li
si" , 8000,
latch);

worker1.start(); //

worker2.start(); //

latch.await(); //等待所有工人完成工作

System. out.println("all
work done at " +sdf.format(new Date())+"
"+Thread.currentThread().getName());

}

static class Worker extends Thread{

String workerName;

int workTime ;

CountDownLatch latch;

public Worker(String workerName ,int workTime ,CountDownLatch
latch){

this.workerName =workerName;

this.workTime =workTime;

this.latch =latch;

}

public void run(){

System. out.println("Worker
" +workerName +"
do work begin at "+sdf.format( new Date()));

doWork(); //工作了

System. out.println("Worker
" +workerName +"
do work complete at "+sdf.format( new Date()));

latch.countDown();//工人完成工作，计数器减一

}

private void doWork(){

try {

Thread. sleep(workTime);

} catch (InterruptedException e)
{

e.printStackTrace();

}

}

}

}