JAVA中主线程等待异步子线程全部执行完后在执行方法（咋个办呢 zgbn）

JAVA中主线程等待异步子线程全部执行完后在执行方法（线程池实现方法）

 

1、通过 ExecutorService executor = Executors.newCachedThreadPool();   创建执行线程池；

2、构造 Worker 类去实现Runnable接口，并在构造器中追加线程计数器CountDownLatch成员属性；

 public class Worker implements Runnable{   
       
    private CountDownLatch downLatch;   
    private String name;   
       
    public Worker(CountDownLatch downLatch, String name){   
        this.downLatch = downLatch;   
        this.name = name;   
    }   
      
    public void run() {   
		//线程执行体
		this.doRun();
		//当子线程执行完成后，计数器减一；
		this.downLatch.countDown();   
	}

	private void doRun(){
        System.out.println("子线程"+this.name+"程执行完成...") ;
	}
}

 3、使用方法；

public static void main(String[] args) {   
	//演示
	ExecutorService executor = Executors.newCachedThreadPool();   
	//创建计数器对象，此处构造器传入的int类型实参，必须与下文需要的创建的子线程个数相同。
	CountDownLatch latch = new CountDownLatch(3);   
	   
	Worker w1 = new Worker(latch,"T1");   
	Worker w2 = new Worker(latch,"T2");   
	Worker w3 = new Worker(latch,"T3");   
	   
	executor.execute(w3);   
	executor.execute(w2);   
	executor.execute(w1);   
		
	executor.shutdown();   
	
	System.out.println("主线程执行完成...") ;
}