搶購限流

Guava RateLimiter

RateLimiter rateLimiter = RateLimiter.create(10,1,TimeUnit.SECONDS);//一秒鐘生產10個令牌

rateLimiter.tryAcquire(1,TimeUnit.SECONDS); //試圖一秒鐘內拿到令牌 
rateLimiter.acquire();//拿令牌 沒有就阻塞線程