計(jì)數(shù)器變?yōu)?后就永遠(yuǎn)為0

public static void main(String[] args) {

    //計(jì)數(shù)器變?yōu)?后就永遠(yuǎn)為0
   //若下面參數(shù)設(shè)置為4,則程序wait一直處于等待中
    CountDownLatch countDownLatch = new CountDownLatch(3);

    IntStream.range(0,3).forEach(i -> new Thread(() -> {
      try {
        Thread.sleep(2000);
        System.out.println("hello");
      } catch (InterruptedException e) {
        e.printStackTrace();
      } finally {
        //計(jì)數(shù)器變?yōu)?后就永遠(yuǎn)為0
        countDownLatch.countDown();
      }
    }).start());

    System.out.println("啟動(dòng)子線程完畢");

    try {
     // countDownLatch.await();
      countDownLatch.await(1, TimeUnit.SECONDS);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }

    System.out.println("主線程執(zhí)行結(jié)束");

  }