Semaphore的使用场景

package com.huang.add;

import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

/**
 * Semaphore模拟抢车位
 */
public class SemaphoreDemo {
    public static void main(String[] args) {
        Semaphore semaphore = new Semaphore(3);

        for (int i = 1; i <= 6; i++) {
            new Thread(() -> {
                try {
                    semaphore.acquire();//如果车位已满，需等待车位释放
                    System.out.println(Thread.currentThread().getName()+"抢到车位");
                    TimeUnit.SECONDS.sleep(2);
                    System.out.println(Thread.currentThread().getName()+"离开车位");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    semaphore.release();//释放车位
                }
            }).start();
        }
    }
}

运行结果