Java并发工具：CountDownLatch与CyclicBarrier的应用案例

原创墨蓝 2024-10-19 15:30 44阅读 0赞

在Java编程中，CountDownLatch和CyclicBarrier是两种常用的并发工具，它们主要用于协调多个线程的执行。

1. CountDownLatch应用案例：

- 多个任务完成后通知主线程：
```java
public class CountDownLatchExample {
    private CountDownLatch countDownLatch;

public CountDownLatchExample(int count) {
        countDownLatch = new CountDownLatch(count);
    }

public void task() throws InterruptedException {
        countDownLatch.countDown();
        System.out.println("Task done");
    }

public static void main(String[] args) {
        CountDownLatchExample example = new CountDownLatchExample(3);

Thread t1 = new Thread(example::task);
        Thread t2 = new Thread(example::task);
        Thread t3 = new Thread(example::task);

t1.start();
        t2.start();
        t3.start();

t1.join();
        t2.join();
        t3.join();

if (countDownLatch.getCount() == 0) {
            System.out.println("All tasks done");
        } else {
            System.out.println("Some tasks not completed yet");
        }
    }
}
```
2. CyclicBarrier应用案例：

- 共享资源的线程组：
```java
import java.util.concurrent.CyclicBarrier;

public class CyclicBarrierExample {
    private CyclicBarrier cyclicBarrier;

public CyclicBarrierExample(int parties) {
        cyclicBarrier = new CyclicBarrier(parties, "Resource sharing barrier"));
    }

public void resourceConsumerThread() throws Exception {
        cyclicBarrier.await();
        // 共享资源操作
        System.out.println("Consumed resource");
    }

public static void main(String[] args) {
        CyclicBarrierExample example = new CyclicBarrierExample(3);

Thread t1 = new Thread(example::resourceConsumerThread));
        Thread t2 = new Thread(example::resourceConsumerThread));
        Thread t3 = new Thread(example::resourceConsumerThread));

t1.start();
        t2.start();
        t3.start();

t1.join();
        t2.join();
        t3.join();
    }
}
```
以上两个例子展示了CountDownLatch和CyclicBarrier在Java并发编程中的具体应用。