import java.util.concurrent.CountDownLatch;

public class Main {
    public static void main(String[] args) {
        int threads = 3;
        final CountDownLatch latch = new CountDownLatch(threads);

        for (int i = 0; i < threads; i++) {
            new Thread(new Worker(latch)).start();
        }

        try {
            // 主线程等待其他线程完成
            latch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("所有线程已到达，主线程继续执行...");
    }

    static class Worker implements Runnable {
        private final CountDownLatch latch;

        Worker(CountDownLatch latch) {
            this.latch = latch;
        }

        @Override
        public void run() {
            try {
                // 模拟工作耗时
                Thread.sleep((long) (Math.random() * 1000));
                System.out.println(Thread.currentThread().getName() + " 完成工作");
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                // 完成工作，计数器减1
                latch.countDown();
            }
        }
    }
}