JSON 入门

　　JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式，非常适合于服务器与 JavaScript 的交互。

具体形式：

1. 对象是一个无序的“‘名称/值’对”集合

　{属性:值,属性:值,属性:值}

   eg: {name:"Peter Zhang",age:21,location:"Shanghai"}

   值（value）可以是双引号括起来的字符串（string）、数值(number)、true、false、 null、对象（object）或者数组（array）。这些结构可以嵌套。

2. 数组是值（value）的有序集合

  [

    {name:"Peter",age:21,location:"Shanghai"},

    {name:"John Zhao",age:25,location:"Beijing"},

    {name:"Tina",age:23,location:"Heibei"},

  ]

C#中JSON的使用

 示例：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.IO;
  4 using System.Runtime.Serialization.Json;
  5 using System.Runtime.Serialization;
  6 using System.Text;
  7 
  8 namespace JSON_Testing
  9 {
 10     [DataContract]
 11     public class Student
 12     {
 13         [DataMember(Order = 0)]
 14         public string Name
 15         {
 16             get;
 17             set;
 18         }
 19 
 20         [DataMember(Order = 1)]
 21         public int Age
 22         {
 23             get;
 24             set;
 25         }
 26 
 27         [DataMember(Order = 2)]
 28         public string Class
 29         {
 30             get;
 31             set;
 32         }
 33 
 34         public override string ToString()
 35         {
 36             return string.Format("Student-> Name:{0}; Age:{1}; Class:{2}", Name, Age, Class);
 37         }
 38     }
 39 
 40     public class JsonObjectConvert
 41     {
 42         /// <summary>
 43         /// Convert Student object to Json string
 44         /// </summary>
 45         /// <param name="stu">student object</param>
 46         /// <returns>json string</returns>
 47         public static string ConvertObjectToJson(Student stu)
 48         {
 49             DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Student));
 50             var stream = new MemoryStream();
 51             serializer.WriteObject(stream, stu);
 52 
 53             byte[] bytes = new byte[stream.Length];
 54 
 55             stream.Position = 0;
 56 
 57             stream.Read(bytes, 0, (int)stream.Length);
 58             stream.Close();
 59 
 60             return Encoding.UTF8.GetString(bytes);
 61         }
 62 
 63         /// <summary>
 64         /// Convert a list of students to Json string
 65         /// </summary>
 66         /// <param name="students">a student collection</param>
 67         /// <returns>json string</returns>
 68         public static string ConvertObjectsToJson(List<Student> students)
 69         {
 70             DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(List<Student>));
 71             var stream = new MemoryStream();
 72             serializer.WriteObject(stream, students);
 73 
 74             byte[] bytes = new byte[stream.Length];
 75 
 76             stream.Position = 0;
 77 
 78             stream.Read(bytes, 0, (int)stream.Length);
 79             stream.Close();
 80 
 81             return Encoding.UTF8.GetString(bytes);
 82         }
 83 
 84         /// <summary>
 85         /// Convert json string to student object
 86         /// </summary>
 87         /// <param name="jsonStr">json string</param>
 88         /// <returns>student object</returns>
 89         public static Student ConvertJsonToObject(string jsonStr)
 90         {
 91             byte[] bytes = Encoding.UTF8.GetBytes(jsonStr);
 92             var stream = new MemoryStream(bytes);
 93 
 94             DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Student));
 95             Student stu = (Student)serializer.ReadObject(stream);
 96 
 97             stream.Close();
 98             return stu;
 99         }
100 
101         /// <summary>
102         /// Convert json string to student list
103         /// </summary>
104         /// <param name="jsonStr">json string</param>
105         /// <returns>student list</returns>
106         public static List<Student> ConvertJsonToObjects(string jsonStr)
107         {
108             byte[] bytes = Encoding.UTF8.GetBytes(jsonStr);
109             var stream = new MemoryStream(bytes);
110 
111             DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(List<Student>));
112             List<Student> students = (List<Student>)serializer.ReadObject(stream);
113 
114             stream.Close();
115             return students;
116         }
117     }
118 
119     class Program
120     {
121         static void Main(string[] args)
122         {
123             Student stu = new Student();
124             stu.Name = "John";
125             stu.Age = 20;
126             stu.Class = "01";
127 
128             Student stu1 = new Student();
129             stu1.Name = "Peter";
130             stu1.Age = 23;
131             stu1.Class = "13";
132 
133             List<Student> list = new List<Student>();
134             list.Add(stu);
135             list.Add(stu1);
136 
137             string stuJson = JsonObjectConvert.ConvertObjectToJson(stu);
138             string stusJson = JsonObjectConvert.ConvertObjectsToJson(list);
139 
140             Console.WriteLine("---------Convert student object to json string---------");
141             Console.WriteLine(stuJson);
142             Console.WriteLine("---------Convert list of student to json string---------");
143             Console.WriteLine(stusJson);
144 
145             Student student = JsonObjectConvert.ConvertJsonToObject(stuJson);
146             List<Student> students = JsonObjectConvert.ConvertJsonToObjects(stusJson);
147 
148             Console.WriteLine("---------Convert json string to student object---------");
149             Console.WriteLine(student);
150 
151             Console.WriteLine("---------Convert json string to list of student---------");
152             foreach (Student s in students)
153             {
154                 Console.WriteLine(s);
155             }
156         }
157     }
158 }

输出：

---------Convert student object to json string---------
{"Name":"John","Age":20,"Class":"01"}
---------Convert list of student to json string---------
[{"Name":"John","Age":20,"Class":"01"},{"Name":"Peter","Age":23,"Class":"13"}]
---------Convert json string to student object---------
Student-> Name:John; Age:20; Class:01
---------Convert json string to list of student---------
Student-> Name:John; Age:20; Class:01
Student-> Name:Peter; Age:23; Class:13