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;  
        }