Java CyclicBarrier

 // parties表示屏障拦截的线程数量，每个线程调用 await 方法告诉 CyclicBarrier 我已经到达了屏障，然后当前线程被阻塞。
 public CyclicBarrier(int parties)
 // 用于在线程到达屏障时，优先执行 barrierAction，方便处理更复杂的业务场景(该线程的执行时机是在到达屏障之后再执行)

//屏障 指定数量的线程全部调用await()方法时，这些线程不再阻塞
// BrokenBarrierException 表示栅栏已经被破坏，破坏的原因可能是其中一个线程 await() 时被中断或者超时
public int await() throws InterruptedException, BrokenBarrierException
public int await(long timeout, TimeUnit unit) throws InterruptedException, BrokenBarrierException, TimeoutException
//循环  通过reset()方法可以进行重置

public class CyclicBarrierTest2 {
    //保存每个学生的平均成绩
    private Conc urrentHashMap<String, Integer> map=new ConcurrentHashMap<String,Integer>();
    private ExecutorService threadPool= Executors.newFixedThreadPool(3);
    private CyclicBarrier cb=new CyclicBarrier(3,()->{
        int result=0;
        Set<String> set = map.keySet();
        for(String s:set){
            result+=map.get(s);
        }
        System.out.println("三人平均成绩为:"+(result/3)+"分");
    });
    public void count(){
        for(int i=0;i<3;i++){
            threadPool.execute(new Runnable(){

                @Override
                public void run() {
                    //获取学生平均成绩
                    int score=(int)(Math.random()*40+60);
                    map.put(Thread.currentThread().getName(), score);
                    System.out.println(Thread.currentThread().getName()
                            +"同学的平均成绩为："+score);
                    try {
                        //执行完运行await(),等待所有学生平均成绩都计算完毕
                        cb.await();
                    } catch (InterruptedException | BrokenBarrierException e) {
                        e.printStackTrace();
                    }
                }

            });
        }
    }
    public static void main(String[] args) {
        CyclicBarrierTest2 cb=new CyclicBarrierTest2();
        cb.count();
    }
}

public class CyclicBarrierTest3 {
    public static void main(String[] args) {
        AtomicInteger counter = new AtomicInteger();
        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                5, 5, 1000, TimeUnit.SECONDS,
                new ArrayBlockingQueue<>(100),
                (r) -> new Thread(r, counter.addAndGet(1) + " 号 "),
                new ThreadPoolExecutor.AbortPolicy());

        CyclicBarrier cyclicBarrier = new CyclicBarrier(5,
                () -> System.out.println("裁判：比赛开始~~"));

        for (int i = 0; i < 10; i++) {
            threadPoolExecutor.submit(new Runner(cyclicBarrier));
        }

    }
    static class Runner extends Thread{
        private CyclicBarrier cyclicBarrier;
        public Runner (CyclicBarrier cyclicBarrier) {
            this.cyclicBarrier = cyclicBarrier;
        }
        @Override
        public void run() {
            try {
                int sleepMills = ThreadLocalRandom.current().nextInt(1000);
                Thread.sleep(sleepMills);
                System.out.println(Thread.currentThread().getName() + " 选手已就位, 准备共用时： " + sleepMills + "ms" + cyclicBarrier.getNumberWaiting());
                cyclicBarrier.await();

            } catch (InterruptedException e) {
                e.printStackTrace();
            }catch(BrokenBarrierException e){
                e.printStackTrace();
            }
        }
    }

}