Java中如何使用CountDownLatch控制线程执行顺序

import java.util.concurrent.CountDownLatch;

public class ThreadOrderExample {
    public static void main(String[] args) {
        // 设置计数器为2，表示等待两个线程完成
        CountDownLatch latch = new CountDownLatch(2);

        Thread threadA = new Thread(() -> {
            System.out.println("Thread A 正在执行");
            try { Thread.sleep(1000); } catch (InterruptedException e) {}
            System.out.println("Thread A 执行完毕");
            latch.countDown(); // 计数减1
        });

        Thread threadB = new Thread(() -> {
            System.out.println("Thread B 正在执行");
            try { Thread.sleep(1500); } catch (InterruptedException e) {}
            System.out.println("Thread B 执行完毕");
            latch.countDown(); // 计数减1
        });

        Thread threadC = new Thread(() -> {
            System.out.println("Thread C 等待 A 和 B 完成...");
            try {
                latch.await(); // 阻塞，直到计数为0
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("Thread C 开始执行");
        });

        // 启动线程（顺序可任意）
        threadC.start();
        threadA.start();
        threadB.start();
    }
}

Thread C 等待 A 和 B 完成...
Thread A 正在执行
Thread B 正在执行
Thread A 执行完毕
Thread B 执行完毕
Thread C 开始执行