内容：一个主任务等待两个子任务，通过CyclicBarrier的await()实现。此Runnable任务在CyclicBarrier的数目达到后，全部其他线程被唤醒前被运行。

public class CyclicBarrierTest {

	class MainTask implements Runnable {

		@Override

		public void run() {

			System.out.println(">>>>主任务開始运行!<<<<");

		}

	}

	class SubTask implements Runnable {

		private String name;

		private CyclicBarrier cyclicBarrier;

		SubTask(String name, CyclicBarrier cyclicBarrier) {

			this.name = name;

			this.cyclicBarrier = cyclicBarrier;

		}

		@Override

		public void run() {

			System.out.println("[子任务" + name + "]開始运行了!");

			for (int i = 0; i < 999999; i++) ;

			System.out.println("[子任务" + name + "]运行完毕了，并通知障碍器已经完毕了");

			try {

				cyclicBarrier.await();

			} catch (InterruptedException  e) {

				e.printStackTrace();

			} catch (BrokenBarrierException e) {

				e.printStackTrace();

			}

		}

	}

	public static void main(String[] args) {

		CyclicBarrierTest test = new CyclicBarrierTest();

		CyclicBarrier cyclicBarrier = new CyclicBarrier(2, test.new MainTask());

		SubTask A = test.new SubTask("A", cyclicBarrier);

		SubTask B = test.new SubTask("B", cyclicBarrier);

		ExecutorService executor = Executors.newCachedThreadPool();

		executor.execute(A);

		executor.execute(B);

	}

}