CyclicBarrier表示大家彼此等待,只有当大家集合完毕之后才开始出发,分散活动后又在指定的地点集合,比如:班级集体活动,先是在校门口集中坐车,所有人到达后,上车走人,到了一个地方自由活动,然后又指定一个吃饭的地方,让等大家集合。
方法:
getNumberWaiting():正在等待的个数(应该加上1)
await():进入等待状态
案例:
public class SyclicBarrierTest { public static void main(String[] args) { /* 创建缓冲性线程池 */ ExecutorService service = Executors.newCachedThreadPool(); /* 创建同步工具对象【表示要3个线程同时到达】 */ final CyclicBarrier cyclicBarrier = new CyclicBarrier(3); /*循环模拟3个线程*/ for (int i = 0; i < 3; i++) { Runnable runnable = new Runnable() { public void run() { try { /* 休眠 */ Thread.sleep((long) (Math.random() * 10000)); System.out.println("线程" + Thread.currentThread().getName() + "即将到达集合地点1,当前已有" + (cyclicBarrier.getNumberWaiting() + 1) + "个已经到达," + (cyclicBarrier.getNumberWaiting() == 2 ? "都到齐了,继续走啊" : "正在等候")); /*线程达到之后进行等待*/ cyclicBarrier.await(); /*休眠*/ Thread.sleep((long) (Math.random() * 10000)); System.out.println("线程" + Thread.currentThread().getName() + "即将到达集合地点2,当前已有" + (cyclicBarrier.getNumberWaiting() + 1) + "个已经到达," + (cyclicBarrier.getNumberWaiting() == 2 ? "都到齐了,继续走啊" : "正在等候")); /*线程到达之后进行等待*/ cyclicBarrier.await(); /*休眠*/ Thread.sleep((long) (Math.random() * 10000)); System.out.println("线程" + Thread.currentThread().getName() + "即将到达集合地点3,当前已有" + (cyclicBarrier.getNumberWaiting() + 1) + "个已经到达," + (cyclicBarrier.getNumberWaiting() == 2 ? "都到齐了,继续走啊" : "正在等候")); /*线程到达之后进行等待*/ cyclicBarrier.await(); } catch (Exception e) { e.printStackTrace(); } } }; service.execute(runnable); } service.shutdown(); } }
程序运行效果: