含有日期类型对象的序列化合反序列化

protected void Page_Load(object sender, EventArgs e)
        {

            Person p = new Person();
            p.Name = "张三";
            p.Age = 28;
            p.LastLoginTime = DateTime.Now;
            string jsonString = JsonSerializer<Person>(p);
        }

        public class Person
        {
            public string Name { get; set; }
            public int Age { get; set; }
            public DateTime LastLoginTime { get; set; }
        }

        /// <summary>
        /// JSON序列化
        /// /// </summary>
       public static string JsonSerializer<T>(T t)
       {
           DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
           MemoryStream ms = new MemoryStream();
           ser.WriteObject(ms, t);
           string jsonString = Encoding.UTF8.GetString(ms.ToArray());
           ms.Close();
           //替换Json的Date字符串
           string p = @"\\/Date\((\d+)\+\d+\)\\/";
           MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString);
           Regex reg = new Regex(p);
           jsonString = reg.Replace(jsonString, matchEvaluator);
           return jsonString;
       }
        /// <summary>
        /// JSON反序列化
        /// </summary>
        public static T JsonDeserialize<T>(string jsonString)
        {
            //将"yyyy-MM-dd HH:mm:ss"格式的字符串转为"\/Date(1294499956278+0800)\/"格式
            string p = @"\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}";
            MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertDateStringToJsonDate);
            Regex reg = new Regex(p);
            jsonString = reg.Replace(jsonString, matchEvaluator);
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
            MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
            T obj = (T)ser.ReadObject(ms);
            return obj;
        }
        /// <summary>
        /// /// 将Json序列化的时间由/Date(1294499956278+0800)转为字符串
        /// </summary>
        private static string ConvertJsonDateToDateString(Match m)
        {
            string result = string.Empty;
            DateTime dt = new DateTime(1970,1,1);
            dt = dt.AddMilliseconds(long.Parse(m.Groups[1].Value));
            dt = dt.ToLocalTime();
            result = dt.ToString("yyyy-MM-dd HH:mm:ss");
            return result;
        }
        /// <summary>
        /// 将时间字符串转为Json时间
        /// </summary>
        private static string ConvertDateStringToJsonDate(Match m)
        {
            string result = string.Empty;
            DateTime dt = DateTime.Parse(m.Groups[0].Value);
            dt = dt.ToUniversalTime();
            TimeSpan ts = dt - DateTime.Parse("1970-01-01");
            result = string.Format("\\/Date({0}+0800)\\/",ts.TotalMilliseconds);
            return result;
        }