信号量的使用案例

import java.util.concurrent.Semaphore;


public class SemaphoreLearn {

    
    public static void main(String[] args) {
        
        Semaphore semaphore = new Semaphore(5, true);
        
        int custom = 100;
        
        for (int i = 0; i < custom; i++) {
            new Thread(new Server(semaphore, i)).start();
        }
        
    }
    
}


class Server implements Runnable {
    
    private Semaphore semaphore;
    
    private int custom;
    
    public Server(Semaphore semaphore, int custom) {
        this.semaphore = semaphore;
        this.custom = custom;
    }
    
    @Override
    public void run() {
        try {
            while(true) {    //如果获取连接失败，则强制等待
                /*if (semaphore.tryAcquire()) {
                    Teller.getService(custom);
                    break;
                }*/
                semaphore.acquire();    //也可以通过这种方式进行，因为该方法是个阻塞方法
                Teller.getService(custom);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            semaphore.release();
        }
    }
}

class Teller {
    public static void getService(int i) {
        System.out.println("servering to custom " + i);
    }
}