如何在多线程程序中使用CountDownLatch

import java.util.concurrent.CountDownLatch;

public class CountDownLatchExample {
    public static void main(String[] args) throws InterruptedException {
        final int numberOfThreads = 5;
        CountDownLatch latch = new CountDownLatch(numberOfThreads);

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

        // 主线程在此等待所有子线程完成
        latch.await();
        System.out.println("All worker threads have finished.");
    }
}

class Worker implements Runnable {
    private final CountDownLatch latch;
    private final int id;

    public Worker(CountDownLatch latch, int id) {
        this.latch = latch;
        this.id = id;
    }

    @Override
    public void run() {
        try {
            System.out.println("Thread " + id + " is working.");
            Thread.sleep((long) (Math.random() * 1000));
            System.out.println("Thread " + id + " has finished.");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            // 计数器减一
            latch.countDown();
        }
    }
}