Java并发编程 CountDownLatch,Semaphore,CyclicBarrier

最新推荐文章于 2025-10-17 21:56:51 发布

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本文通过三个实例详细介绍了Java中三种重要的并发控制机制：CountDownLatch、Semaphore及CyclicBarrier的使用方法。CountDownLatch允许一个或多个线程等待其他线程完成操作；Semaphore用于控制对资源的访问数量；CyclicBarrier则让所有线程达到屏障点后继续运行。

public class CountDownLatchApp {

    public CountDownLatch countDownLatch = new CountDownLatch(100);

    public Semaphore semaphore = new Semaphore(1);

    public CyclicBarrier cyclicBarrier = new CyclicBarrier(100);

    public static void main(String[] args) throws Exception {
        cyclicBarrierTest();
        countDownLatchTest();
        semaphoreTest();
    }

    public static void cyclicBarrierTest() throws Exception {
        final CountDownLatchApp app = new CountDownLatchApp();
        for (int i = 0; i < 99; i++) {
            new Thread(new Runnable() {
                public void run() {
                    try {
                        Thread.sleep(1000);
                        System.out.println(Thread.currentThread().getName());
                        app.cyclicBarrier.await();
                        System.out.println(Thread.currentThread().getName() + "await");
                    } catch (Exception e) {

                    }
                }
            }).start();
        }
        System.out.println("Main");
        app.cyclicBarrier.await();
        System.out.println("MainEnd");
    }

    public static void countDownLatchTest() throws Exception {
        final CountDownLatchApp app = new CountDownLatchApp();
        for (int i = 0; i < 99; i++) {
            new Thread(new Runnable() {
                public void run() {
                    try {
                        Thread.sleep(1000);
                        System.out.println(Thread.currentThread().getName());
                        app.countDownLatch.countDown();
                    } catch (Exception e) {

                    }
                }
            }).start();
        }
        System.out.println("Main");
        app.countDownLatch.countDown();
        app.countDownLatch.await();
        System.out.println("MainEnd");
    }

    public static void semaphoreTest() throws Exception {
        final CountDownLatchApp app = new CountDownLatchApp();
        for (int i = 0; i < 99; i++) {
            new Thread(new Runnable() {
                public void run() {
                    try {
                        app.semaphore.acquire();
                        Thread.sleep(1000);
                        System.out.println(Thread.currentThread().getName());
                        app.semaphore.release();
                    } catch (Exception e) {

                    }
                }
            }).start();
        }
        app.semaphore.acquire();
        System.out.println("Main");
        System.out.println("MainEnd");
        app.semaphore.release();
    }

}