Java并发之countdownlatch Java并发知识点笔记

//{java}
package 使用CountDownLatch来控制线程执行的先后顺序;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class CountDownLatchTest {
	public static void main(String []args) throws InterruptedException
	{
		ExecutorService exec = Executors.newCachedThreadPool();
		CountDownLatch latch = new CountDownLatch(2);
		exec.execute(new Task(1, latch));
		exec.execute(new Task(2, latch));
		latch.await();
		System.out.println("主线程结束");
	}

}

class Task implements Runnable
{
	int id;
	CountDownLatch latch;
	
	public Task(int id, CountDownLatch latch) {
		super();
		this.id = id;
		this.latch = latch;
	}

	@Override
	public void run() {
		System.out.println(id+"开始工作");
		try {
			Thread.sleep(2000);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		System.out.println(id+"工作完成");
		latch.countDown();
		
	}
	
}