public class CyclicBarrierDemo {

     private static final int THREAD_NUM = 5;

     public static class WorkerThread implements Runnable {

         CyclicBarrier barrier;

         public WorkerThread(CyclicBarrier b) {

             this.barrier = b;

         }

         public void run() {

             try {

                 System.out.println("Worker's waiting");

                 //线程在这里等待，直到所有线程都到达barrier

                 barrier.await();

                 System.out.println("ID:" + Thread.currentThread().getId() + " Working");

             } catch (Exception e) {

                 e.printStackTrace();

             }

         }

     }

     public static void main(String[] args) {

         //当所有线程到达barrier时执行

         CyclicBarrier cb = new CyclicBarrier(THREAD_NUM, () -> System.out.println("Inside Barrier"));

         for (int i = 0; i < THREAD_NUM; i++) {

             new Thread(new WorkerThread(cb)).start();

         }

     }

 }

Worker's waiting

Worker's waiting

Worker's waiting

Worker's waiting

Worker's waiting

Inside Barrier

ID: Working

ID: Working

ID: Working

ID: Working

ID: Working