一文详解Java闭锁和栅栏的实现

package cn.xiaoxuzhu.daily;
 
import java.util.concurrent.CountDownLatch;
 
public class AbcTest {
    public static void main(String[] args) {
        CountDownLatch countDownLatch =new CountDownLatch(2);
        //线程A
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
 
                }catch (InterruptedException e){
                    e.printStackTrace();
 
                }
                System.out.println(Thread.currentThread().getName()+":"+"线程A执行结束");
                countDownLatch.countDown();
            }
        },"线程A").start();
        //线程B
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);
                }catch (InterruptedException e){
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+":"+"线程B执行结束");
                countDownLatch.countDown();
            }
 
        },"线程B").start();
 
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                  countDownLatch.await();
                }catch (InterruptedException e){
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+":"+"线程C执行结束");
                countDownLatch.countDown();
            }
 
        },"线程C").start();
 
    }
}

package cn.xiaoxuzhu.daily;
 
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
/**
 * Description: 有3个线程。线程A和线程B并行执行，线程C需要A和B执行完成后才能执行。可以怎么实现？
 *
 * @author 小王同学
 * @version 1.0
 * @Description: */
 
public class AbcTest2 {
 
    public static void main(String[] args) {
        CyclicBarrier cyclicBarrier=new CyclicBarrier(3);
        //线程A
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+":"+"线程A执行结束");
                try {
                    cyclicBarrier.await();//符合三个线程都到达栅栏才往下执行
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                }
            }
        },"线程A").start();
 
        //线程B
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+":"+"线程B执行结束");
                try {
                    cyclicBarrier.await();//符合三个线程都到达栅栏才往下执行
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                }
            }
        },"线程B").start();
 
        //线程C
        new Thread(new Runnable() {
            @Override
            public void run() {
                //等待A,B线程完成
                try {
                    cyclicBarrier.await();//符合三个线程都到达栅栏才往下执行
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+":"+"线程C执行结束");
            }
        },"线程C").start();
    }
}