支付宝面试题--限制接口10分钟50次调用

利用redis，实现对接口的10分钟50次调用限制
每来请求，加入redis
如果队列满了，看看当前请求与前面第50次请求时间差
如果在10分钟内就拒绝，否则就加入队列，删除最前面的哪一个

                String keyOflimit10min = "keyOflimit10min";
                Long count = redisTemplate.opsForList().size(keyOflimit10min);
            	int requestCount = 50;
            	int timeRangeSec = 10*60;  //10分钟内，50次请求
            	
            	if (count >requestCount) {
            		redisTemplate.delete(keyOflimit10min);
            	}
            	if (count ==0 || count < requestCount) {
            		redisTemplate.opsForList().leftPush(keyOflimit10min, String.valueOf(System.currentTimeMillis()));
            	} else {
            		long nowTime   = System.currentTimeMillis();
            		long beginTime = Long.parseLong(redisTemplate.opsForList().index(keyOflimit10min, -1));
            		long gap = nowTime - beginTime;
            		if (gap >0 && gap