CountDownLatch

        int threadCount = 10;
        CountDownLatch latch = new CountDownLatch(threadCount);
        for (int i = 0; i < 1000; i++) {
            new Thread(()->{
          
                System.out.println("我是线程:");
            }).start();
            latch.countDown();
        }
        try {
            latch.await();
        } catch (InterruptedException e) {
            // await会抛出异常
            e.printStackTrace();
        }
        System.out.println("所有线程执行完毕 " +integerThreadLocal.get());