一、JSON简介

JSON(JavaScript Object Notation,JavaScript对象表示法)是一种轻量级的数据交换格式。

JSON是“名值对”的集合。结构由大括号'{}'，中括号'[]'，逗号'，'，冒号'：'，双引号'“”'组成，包含的数据类型有Object，Number,Boolean,String,Array, NULL等。

JSON具有以下的形式：

对象(Object)是一个无序的“名值对”集合，一个对象以”{”开始,”}”结束。每个“名”后跟着一个”:”,多个“名值对”由逗号分隔。如：

{"FirstName":"Jason","LastName":"Chen"}

数组(Array)是值的有序集合，一个数组以“[”开始,以“]”结束，值之间使用“,”分隔。如：

[{"FirstName":"Jason","LastName":"Chen"},{"FirstName":"Jason","LastName":"Chen"}]

字符串(String)是由双引号包围的任意数量的Unicode字符的集合，使用反斜线转义。

二、对JSON数据进行序列化和反序列化

可以使用DataContractJsonSerializer类将类型实例序列化为JSON字符串，并将JSON字符串反序列化为类型实例。

利用DataContractJsonSerializer序列化和反序列化的代码：

using System;

using System.IO;

using System.Runtime.Serialization.Json;

using System.Text;

using System.Text.RegularExpressions;

/*

 *  DataContractJsonSerializer在System.Runtime.Serialization.Json命名空间下，

 *  .NET Framework 3.5包含在System.ServiceModel.Web.dll中；

 *  .NET Framework 4.0包含在System.Runtime.Serialization中。

 *  create by cjj on 2014-10-08;email:ijasonchen91@sina.com<span style="font-family: Arial, Helvetica, sans-serif;">。</span>

 */

namespace mob.json

{

    /// <summary>

    /// JSON序列化和反序列化辅助类

    /// </summary>

    public class JsonHelper

    {

        /// <summary>

        /// JSON序列化

        /// </summary>

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

        /// <param name="t"></param>

        /// <returns></returns>

        public static string Serialize<T>(T t)

        {

            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));

            MemoryStream ms = new MemoryStream();

            serializer.WriteObject(ms, t);

            string jsonString = Encoding.Default.GetString(ms.ToArray());

            ms.Close();

            jsonString = ConvertToDateTimeString(jsonString);

            return jsonString;

        }

        /// <summary>

        /// JSON反序列化

        /// </summary>

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

        /// <param name="jsonString"></param>

        /// <returns></returns>

        public static T Deserialize<T>(string jsonString)

        {

            jsonString = ConvertToJsonDateTimeString(jsonString);

            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));

            MemoryStream ms = new MemoryStream(Encoding.Unicode.GetBytes(jsonString));

            T obj = (T)serializer.ReadObject(ms);

            ms.Close();

            return obj;

        }

        /// <summary>

        /// 将"\/Date(673286400000+0800)\/"Json时间格式替换"yyyy-MM-dd HH:mm:ss"格式的字符串

        /// </summary>

        /// <param name="jsonDateTimeString">"\/Date(673286400000+0800)\/"Json时间格式</param>

        /// <returns></returns>

        private static string ConvertToDateTimeString(string jsonDateTimeString)

        {

            string result = string.Empty;

            string p = @"\\/Date\((\d+)\+\d+\)\\/";

            MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString);

            Regex reg = new Regex(p);

            result = reg.Replace(jsonDateTimeString, matchEvaluator);

            return result;

        }

        private static string ConvertJsonDateToDateString(Match match)

        {

            string result = string.Empty;

            DateTime dt = new DateTime(1970, 1, 1);

            dt = dt.AddMilliseconds(long.Parse(match.Groups[1].Value));

            dt = dt.ToLocalTime();

            result = dt.ToString("yyyy-MM-dd HH:mm:ss");

            return result;

        }

        /// <summary>

        /// 将"yyyy-MM-dd HH:mm:ss"格式的字符串替换"\/Date(673286400000+0800)\/"Json时间格式

        /// </summary>

        /// <param name="dateTimeString">"yyyy-MM-dd HH:mm:ss"格式的字符串</param>

        /// <returns></returns>

        private static string ConvertToJsonDateTimeString(string dateTimeString)

        {

            string result = string.Empty;

            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);

            result = reg.Replace(dateTimeString, matchEvaluator);

            return result;

        }

        private static string ConvertDateStringToJsonDate(Match match)

        {

            string result = string.Empty;

            DateTime dt = DateTime.Parse(match.Groups[0].Value);

            dt = dt.ToUniversalTime();

            TimeSpan ts = dt - DateTime.Parse("1970-01-01");

            result = string.Format("\\/Date({0}+0800)\\/", ts.TotalMilliseconds);

            return result;

        }

    }

}

序列化Demo：

简单对象Person：

[DataContract]

public class Person

{

    public Person() { }

    public Person(string firstname, string lastname, DateTime birthday)

    {

        this.FirstName = firstname;

        this.LastName = lastname;

        this.Birthday = birthday;

    }

    [DataMember]

    public string FirstName { get; set; }

    [DataMember]

    public string LastName { get; set; }

    [DataMember]

    public DateTime Birthday { get; set; }

}

序列化为JSON字符串：

private void Serialize()

{

    Person p = new Person("Jason", "Chen", Convert.ToDateTime("1991-05-04"));

    string jsonString = JsonHelper.Serialize<Person>(p);

    Response.Write(jsonString);

}

输出结果：

{"Birthday":"1991-05-04 00:00:00","FirstName":"Jason","LastName":"Chen"}

反序列化Demo：

private static void Deserialize()

{

    string jsonString = "{\"FirstName\":\"Jason\",\"LastName\":\"Chen\",\"Birthday\":\"1991-05-04 00:00:00\"}";

    Person p = JsonHelper.Deserialize<Person>(jsonString);

}

运行结果：

三、JSON序列化集合、字典、数组的处理

在JSON数据中，所有的集合、字典和数组都表示为数组。

List<T>序列化:

private void Serialize()

{

    List<Person> list = new List<Person>(){

        new Person("Jason", "Chen", Convert.ToDateTime("1991-05-04")),

        new Person("Jack", "Chen", Convert.ToDateTime("1991-05-05"))

    };

    string jsonString = JsonHelper.Serialize<List<Person>>(list);

    Response.Write(jsonString);

}

序列化结果：

[{"Birthday":"1991-05-04 00:00:00","FirstName":"Jason","LastName":"Chen"},{"Birthday":"1991-05-05 00:00:00","FirstName":"Jack","LastName":"Chen"}]

Dictionary字典转化为JSON，如：

private void Serialize()

{

    Dictionary<string, string> dic = new Dictionary<string, string>();

    dic.Add("FirstName", "Jason");

    dic.Add("LastName", "Chen");

    string jsonString = JsonHelper.Serialize<Dictionary<string, string>>(dic);

    Response.Write(jsonString);

}

序列化结果：

[{"Key":"FirstName","Value":"Jason"},{"Key":"LastName","Value":"Chen"}]