java使用CountDownLatch实现多线程协作

//任务分割的线程数
private static final int THREAD_TOTAL = 10;

//子线程执行的超时时间
private static final int countDownLatchTimeout = 5;

public static void main(String[] args) {
    //创建CountDownLatch并设置计数值，该count值可以根据线程数的需要设置
    CountDownLatch countDownLatch = new CountDownLatch(THREAD_TOTAL);

    //创建线程池，开启、创建异步线程执行任务
    ExecutorService cachedThreadPool = Executors.newCachedThreadPool();
    for (int i = 0; i < THREAD_TOTAL; i++) {
        cachedThreadPool.execute(() -> {
            try {
                Thread.sleep(5000);
                System.out.println(Thread.currentThread().getName() + " do something!");
            } catch (Exception e) {
                System.out.println("Exception: do something exception");
            } finally {
                //该线程执行完毕-1
                countDownLatch.countDown();
            }
        });
    }

    //回到主线程中
    System.out.println("Back main thread do something");
    try {
        //主线程等待线程池中完成（子线程执行超时时间）
        boolean await = countDownLatch.await(countDownLatchTimeout, TimeUnit.MINUTES);
        System.out.println(await);
    } catch (InterruptedException e) {
        System.out.println("Exception: await interrupted exception");
    } finally {
        System.out.println("countDownLatch: " + countDownLatch);
    }
    System.out.println("main thread do something-2");
}

/**
 * Synchronization control For CountDownLatch.
 * Uses AQS state to represent count.
 */
private static final class Sync extends AbstractQueuedSynchronizer {
    private static final long serialVersionUID = 4982264981922014374L;

    Sync(int count) {
        setState(count);
    }

    int getCount() {
        return getState();
    }

    protected int tryAcquireShared(int acquires) {
        return (getState() == 0) ? 1 : -1;
    }

    protected boolean tryReleaseShared(int releases) {
        // Decrement count; signal when transition to zero
        for (;;) {
            int c = getState();
            if (c == 0)
                return false;
            int nextc = c-1;
            if (compareAndSetState(c, nextc))
                return nextc == 0;
        }
    }
}

private final Sync sync;


public CountDownLatch(int count) {
    if (count < 0) throw new IllegalArgumentException("count < 0");
    this.sync = new Sync(count);
}


public void await() throws InterruptedException {
    sync.acquireSharedInterruptibly(1);
}

protected boolean tryReleaseShared(int releases) {
    // Decrement count; signal when transition to zero
    for (;;) {
        int c = getState();
        if (c == 0)
            return false;
        int nextc = c-1;
        if (compareAndSetState(c, nextc))
            return nextc == 0;
    }
}