public class TestSemaphore {
 public static void main(String[] args) {
  final Semaphore semaphore = new Semaphore(5);
  ExecutorService executorService = Executors.newCachedThreadPool();
  for(int i = 0;i<10;i++){
   int j = 0;
   executorService.submit(new A("car"+(j++),semaphore),"Thread"+(j++));
   //new Thread(new A("car"+(j++),semaphore),"Thread"+(j++)).start();
   if(i == 5){
    try {
     Thread.sleep(1000);
     System.out.println("最后還有"+semaphore.availablePermits()+"個許可可用");
    } catch (InterruptedException e) {
     e.printStackTrace();
    }
   }
  }

  System.out.println("最后還有"+semaphore.availablePermits()+"個許可可用");
 }

 }
 class A implements Runnable{
  String carName;
  private Semaphore semaphore;

  public A(String carName, Semaphore semaphore){
   this.carName = carName;
   this.semaphore = semaphore;
  }

  public void getWay(){
   System.out.println("this car is get the way" + Thread.currentThread().getName());
  }

  public void run() {
   try {
    if(semaphore.availablePermits() > 0){
     semaphore.acquire();
     getWay();
     semaphore.release();
    }else{
     System.out.println("請等待========");
    }
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  }
 }