使用redis实现分布式环境下的流量控制

public class FlowControl {
	private static Logger logger = LoggerFactory.getLogger(FlowControl.class);

	/**
	 * @Title: allow @Description: 进行流量控制,允许访问返回true 不允许访问返回false 
	 * @param: @param key 放入redis的key，放入前要在key之前添加前缀 前缀配置在eds.properties中的 redis.prefix
	 * @param: @param timeOut 超时时间单位秒
	 * @param: @param count 超时时间内允许访问的次数
	 * @param: @return
	 * @param: @throws
	 *             Exception @return: boolean @throws
	 */
	public static boolean allow(String key, int timeOut, int count) {

		Boolean useFc = Boolean.valueOf(EdsPropertiesUtil.getInstance().getProperty("flowControl.use"));
		// 若不使用流量控制直接返回true
		if (!useFc) {
			return true;
		}

		boolean result = false;
		Jedis jedis = null;
		String prefix = EdsPropertiesUtil.getInstance().getProperty("redis.prefix");
		key = prefix + key;
		try {
			jedis = RedisUtil.getJedis();
			Long newTimes = null;
			Long pttl = jedis.pttl(key);

			if (pttl > 0) {
				newTimes = jedis.incr(key);
				if (newTimes > count) {
					logger.info("key:{},超出{}秒内允许访问{}次的限制,这是第{}次访问", new Object[] { key, timeOut, count, newTimes });
				} else {
					result = true;
				}
			} else if (pttl == -1 || pttl == -2 || pttl == 0) {

				Transaction tx = jedis.multi();
				Response<Long> rsp1 = tx.incr(key);
				tx.expire(key, timeOut);
				tx.exec();
				newTimes = rsp1.get();
				if (newTimes > count) {
					logger.info("key:{},{}秒内允许访问{}次,第{}次访问", new Object[] { key, timeOut, count, newTimes });
				} else {

					result = true;
				}

			}
			if (result) {
				logger.debug("key:{},访问次数{}", new Object[] { key, newTimes });
			}

		} catch (Exception e) {
			logger.error("流量控制发生异常", e);
			e.printStackTrace();
			// 当发生异常时 允许访问
			result = true;
		} finally {
			jedis.close();
		}

		return result;

	}

}