深入理解JUC：第六章：Semaphore信号灯

public class Demo {
    public static void main(String[] args) throws Exception{
        //模拟三个停车位
        Semaphore semaphore = new Semaphore(3);
        //模拟六台车
        for (int i = 1; i <= 6; i++) {
            new Thread(()->{
                try {
                    semaphore.acquire();//减一
                    //semaphore.release();//加一
                    //semaphore.release(2);//加二
                    System.out.println(Thread.currentThread().getName()+"\t 抢到车位");
                    Thread.sleep(2000);
                    System.out.println(Thread.currentThread().getName()+"\t 停车2秒后离开车位");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    semaphore.release();
                }
            },String.valueOf(i)).start();
        }
    }
}