/// <summary>

        /// 判断key是否存在

        /// </summary>

        /// <param name="key"></param>

        /// <param name="db"></param>

        /// <returns></returns>

        public bool KeyExists(string key, int db = -)

        {

            try

            {

                _db = GetDatabase(db);

                return KeyExists(key);

            }

            catch (Exception)

            {

                throw;

            }

        }

        /// <summary>

        /// 根据key 移除缓存

        /// </summary>

        /// <param name="key"></param>

        /// <returns></returns>

        public bool Remove(string key, int db = -)

        {

            try

            {

                if ((object)key == null)

                    return false;

                _db = GetDatabase(db);

                return KeyDelete(key);

            }

            catch (Exception ex)

            {

                _log.Fatal("移除:{0}异常:{1}", key, ex.Message);

                throw;

            }

        }

        /// <summary>

        /// 写入缓存数据

        /// </summary>

        /// <typeparam name="T">类型</typeparam>

        /// <param name="key"></param>

        /// <param name="value"></param>

        /// <param name="span">有效期</param>

        /// <returns></returns>

        public bool Set<T>(string key, T value, TimeSpan span, int db = -)

        {

            try

            {

                if ((object)key == null || value == null)

                    return false;

                _db = GetDatabase(db);

                if (value != null && (object)value is string)

                {

                    return StringSet(key, value.ToString(), span);

                }

                return StringSet<T>(key, value, span);

            }

            catch (Exception ex)

            {

                _log.Fatal("{0}key写入value:{1}失败,异常原因:{2}", key, value, ex.Message);

                throw;

            }

        }

        /// <summary>

        /// 读取缓存数据  返回实体

        /// </summary>

        /// <typeparam name="T"></typeparam>

        /// <param name="key"></param>

        /// <returns></returns>

        public T Get<T>(string key, int db = -)

        {

            try

            {

                _db = GetDatabase(db);

                return StringGet<T>(key);

            }

            catch (Exception)

            {

                throw;

            }

        }

        /// <summary>

        /// 读取缓存数据 返回字符串

        /// </summary>

        /// <param name="key"></param>

        /// <returns></returns>

        public string Get(string key, int db = -)

        {

            try

            {

                _db = GetDatabase(db);

                return StringGet(key);

            }

            catch (Exception)

            {

                throw;

            }

        }

        /// <summary>

        /// 递增

        /// </summary>

        /// <param name="key"></param>

        /// <param name="span"></param>

        /// <param name="db"></param>

        /// <returns></returns>

        public long Increment(string key, TimeSpan span, int db = -)

        {

            try

            {

                _db = GetDatabase(db);

                var result = this.StringIncr(key);

                //设置过期时间

                this.KeyExpire(key, span);

                return result;

            }

            catch (Exception)

            {

                throw;

            }

        }

        /// <summary>

        /// 递减

        /// </summary>

        /// <param name="key"></param>

        /// <param name="span"></param>

        /// <param name="db"></param>

        /// <returns></returns>

        public long Decrement(string key, TimeSpan span, int db = -)

        {

            try

            {

                _db = GetDatabase(db);

                var result = this.StringDecr(key);

                //设置过期时间

                this.KeyExpire(key, span);

                return result;

            }

            catch (Exception)

            {

                throw;

            }

        }