线程同步辅助类的使用

devtools/2025/2/27 8:24:48/

一、countDownLatch(减法)

public class CountDownLatchDemo {public static void main(String[] args) throws InterruptedException {CountDownLatch countDownLatch = new CountDownLatch(6);for (int i = 0; i < 6; i++) {new Thread(()->{System.out.println(Thread.currentThread().getName()+"OUT_OF");countDownLatch.countDown();}).start();}countDownLatch.await();System.out.println("Close Door");}
}

1、可以理解成countDown（）一次就减一直到0结束

2、countDownLatch.await();可以设置超时时间如：

countDownLatch.await(8, TimeUnit.SECONDS);

超时会抛出异常

二、CyclicBarrier（加法）

public class CyclicBarrierDemo {public static void main(String[] args) throws BrokenBarrierException, InterruptedException {//设置阻碍 达到数量 执行CyclicBarrier c = new CyclicBarrier(7, () -> {System.out.println("召唤神龙成功");});for (int i = 0; i < 3; i++) {final int temp=i;new Thread(()->{System.out.println(Thread.currentThread().getName()+"-----------------"+"收集第"+temp+"龙珠");try {c.await(4, TimeUnit.SECONDS);} catch (InterruptedException e) {} catch (Exception e) {throw new RuntimeException(e);};System.out.println("第"+temp+"龙珠");}).start();}}
}

1、调用一次await() 就加1 到达指定数量结束

2、c.await();也可以设置超时时间

三、Semaphore

public class SemaphoreDemo {public static void main(String[] args) {//线程数量Semaphore semaphore = new Semaphore(3);for (int s = 0; s < 6; s++) {final int temp=s;new Thread(()->{try {semaphore.acquire();System.out.println(Thread.currentThread().getName()+"获取第"+temp+"停车位");TimeUnit.SECONDS.sleep(3);System.out.println(Thread.currentThread().getName()+"释放第"+temp+"停车位");} catch (InterruptedException e) {throw new RuntimeException(e);} finally {semaphore.release();}},String.valueOf(s)).start();}}
}