10_Semaphore.md

Semaphore 是一个计数信号量，用于控制同时访问特定资源的线程数量。它通过协调各个线程，以保证合理的使用资源。

一个使用Semaphore来控制停车场的示例

package io.alex.concurrent;
import java.util.concurrent.Semaphore;
public class ParkingSemaphoreExample {
    // 停车场同时容纳的车辆数
    private int count = 100;
    // 停车场
    private Semaphore semaphore = new Semaphore(count);

    public void park() {
        try {
            semaphore.acquire();
            System.out.println(Thread.currentThread().getName() + "进入停车场，剩余车位：" + semaphore.availablePermits());
            Thread.sleep(new java.util.Random().nextInt(24000));
            System.out.println(Thread.currentThread().getName() + "离开停车场，剩余车位：" + semaphore.availablePermits());
            semaphore.release();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) throws InterruptedException {
        ParkingSemaphoreExample parking = new ParkingSemaphoreExample();
        for (int i = 0; i < 200; i++) {
            Thread.sleep(100);
            new Thread(() -> parking.park()).start();
        }
    }
}