Java并发编程：CountDownLatch和Semaphore应用示例-蒲公英云

Java并发编程：CountDownLatch和Semaphore应用示例

在Java并发编程中，CountDownLatch和Semaphore都是线程同步工具，用于控制多个线程的执行顺序。这里分别给出它们的应用示例：

CountDownLatch：
CountDownLatch是一个单向共享计数信号。当一个线程调用await方法时，该线程会阻塞直到CountDownLatch的值减少到0。

示例代码：

import java.util.concurrent.CountDownLatch;
public class CountDownLatchExample {
    private final CountDownLatch countDownLatch = new CountDownLatch(1);
    public void startThread() throws InterruptedException {
        countDownLatch.countDown();
        System.out.println("Thread 1 started");
        // 线程睡眠一段时间，以确保CountDownLatch的值减少
        Thread.sleep(2000);
    }
    public static void main(String[] args) throws InterruptedException {
        CountDownLatchExample example = new CountDownLatchExample();
        Thread thread1 = new Thread(() -> example.startThread()));
        Thread thread2 = new Thread(() -> example.startThread()));
        // 启动两个线程
        thread1.start();
        thread2.start();
        // 等待所有线程执行完毕
        thread1.join();
        thread2.join();
        System.out.println("All threads have finished");
    }
}