等待异步线程池跑完再执行后续代码的方法

等待异步线程池跑完再执行指定方法的三种方式(condition、CountDownLatch、CyclicBarrier)，最近本人使用的CountDownLatch

CountDownLatch应用场景

某个线程需要在其他n个线程执行完毕后再向下执行
多个线程并行执行同一个任务，提高响应速度

public class CountDownLaunchTest {

    public static void main(String[] args) throws InterruptedException {
        List list = new ArrayList();
        for(int i = 1; i<=100; i++){
            list.add(i);
        }
        Long start = System.currentTimeMillis();
        for(int i = 0; i<list.size(); i++){
            Thread.sleep(100);
        }
        System.out.println("=====同步执行：耗时"+(System.currentTimeMillis()-start)+"毫秒======");
        Long start1 = System.currentTimeMillis();
        CountDownLatch latch = new CountDownLatch(10);
        for(int i = 0; i<latch.getCount(); i++){
            new Thread(new Test(latch, i, list)).start();
        }
        latch.await();
        System.out.println("=====异步执行：耗时"+(System.currentTimeMillis()-start1)+"毫秒======");
    }

    static class Test implements Runnable{
        private CountDownLatch latch;
        private int i;
        private List list;
        Test(CountDownLatch latch, int i, List list){
            this.latch = latch;
            this.i = i;
            this.list = list;
        }

        @SneakyThrows
        @Override
        public void run() {
            for(int a = i*10; a<(i+1)*10; a++){
                // 执行任务逻辑
                Thread.sleep(100);
            }
            latch.countDown();
        }
    }
}