抢购限流

Guava RateLimiter

RateLimiter rateLimiter = RateLimiter.create(10,1,TimeUnit.SECONDS);//一秒钟生产10个令牌

rateLimiter.tryAcquire(1,TimeUnit.SECONDS); //试图一秒钟内拿到令牌 
rateLimiter.acquire();//拿令牌 没有就阻塞线程