Newtonsoft.Json学习笔记

Newtonsoft.Json，一款.NET中开源的Json序列化和反序列化类库(下载地址http://json.codeplex.com/)。

下面是Json序列化和反序列化的简单封装：

 /// <summary>
     /// Json帮助类
     /// </summary>
     public class JsonHelper
     {
         /// <summary>
         /// 将对象序列化为JSON格式
         /// </summary>
         /// <param name="o">对象</param>
         /// <returns>json字符串</returns>
         public static string SerializeObject(object o)
         {
             string json = JsonConvert.SerializeObject(o);
             return json;
         }

         /// <summary>
         /// 解析JSON字符串生成对象实体
         /// </summary>
         /// <typeparam name="T">对象类型</typeparam>
         /// <param name="json">json字符串(eg.{"ID":"112","Name":"石子儿"})</param>
         /// <returns>对象实体</returns>
         public static T DeserializeJsonToObject<T>(string json) where T : class
         {
             JsonSerializer serializer = new JsonSerializer();
             StringReader sr = new StringReader(json);
             object o = serializer.Deserialize(new JsonTextReader(sr), typeof(T));
             T t = o as T;
             return t;
         }

         /// <summary>
         /// 解析JSON数组生成对象实体集合
         /// </summary>
         /// <typeparam name="T">对象类型</typeparam>
         /// <param name="json">json数组字符串(eg.[{"ID":"112","Name":"石子儿"}])</param>
         /// <returns>对象实体集合</returns>
         public static List<T> DeserializeJsonToList<T>(string json) where T : class
         {
             JsonSerializer serializer = new JsonSerializer();
             StringReader sr = new StringReader(json);
             object o = serializer.Deserialize(new JsonTextReader(sr), typeof(List<T>));
             List<T> list = o as List<T>;
             return list;
         }

         /// <summary>
         /// 反序列化JSON到给定的匿名对象.
         /// </summary>
         /// <typeparam name="T">匿名对象类型</typeparam>
         /// <param name="json">json字符串</param>
         /// <param name="anonymousTypeObject">匿名对象</param>
         /// <returns>匿名对象</returns>
         public static T DeserializeAnonymousType<T>(string json, T anonymousTypeObject)
         {
             T t = JsonConvert.DeserializeAnonymousType(json, anonymousTypeObject);
             return t;
         }
     }

为进一步理解Newtonsoft，写了一些测试的例子：

     /// <summary>
     /// Json测试
     /// </summary>
     public class JsonTest : IRun
     {
         public void Run()
         {
             Student sdudent = new Student();
             sdudent.ID = ;
             sdudent.Name = "陈晨";
             sdudent.NickName = "石子儿";
             sdudent.Class = new Class() { Name = "CS0216", ID =  };

             //实体序列化和反序列化
             string json1 = JsonHelper.SerializeObject(sdudent);
             //json1 : {"ID":1,"Name":"陈晨","NickName":"石子儿","Class":{"ID":216,"Name":"CS0216"}}
             Student sdudent1 = JsonHelper.DeserializeJsonToObject<Student>(json1);

             //实体集合序列化和反序列化
             List<Student> sdudentList = new List<Student>() { sdudent, sdudent1 };
             string json2 = JsonHelper.SerializeObject(sdudentList);
             //json: [{"ID":1,"Name":"陈晨","NickName":"石子儿","Class":{"ID":216,"Name":"CS0216"}},{"ID":1,"Name":"陈晨","NickName":"石子儿","Class":{"ID":216,"Name":"CS0216"}}]
             List<Student> sdudentList2 = JsonHelper.DeserializeJsonToList<Student>(json2);

             //DataTable序列化和反序列化
             DataTable dt = new DataTable();
             dt.TableName = "Student";
             dt.Columns.Add("ID", typeof(int));
             dt.Columns.Add("Name");
             dt.Columns.Add("NickName");
             DataRow dr = dt.NewRow();
             dr["ID"] = ;
             dr["Name"] = "战三";
             dr["NickName"] = "小三";
             dt.Rows.Add(dr);
             string json3 = JsonHelper.SerializeObject(dt);
             //json3 : [{"ID":112,"Name":"战三","NickName":"小三"}]
             DataTable sdudentDt3 = JsonHelper.DeserializeJsonToObject<DataTable>(json3);
             List<Student> sdudentList3 = JsonHelper.DeserializeJsonToList<Student>(json3);

             //验证对象和数组
             Student sdudent4 = JsonHelper.DeserializeJsonToObject<Student>("{\"ID\":\"112\",\"Name\":\"石子儿\"}");
             List<Student> sdudentList4 = JsonHelper.DeserializeJsonToList<Student>("[{\"ID\":\"112\",\"Name\":\"石子儿\"}]");

             //匿名对象解析
             var tempEntity = new { ID = , Name = string.Empty };
             string json5 = JsonHelper.SerializeObject(tempEntity);
             //json5 : {"ID":0,"Name":""}
             tempEntity = JsonHelper.DeserializeAnonymousType("{\"ID\":\"112\",\"Name\":\"石子儿\"}", tempEntity);
             var tempStudent = new Student();
             tempStudent = JsonHelper.DeserializeAnonymousType("{\"ID\":\"112\",\"Name\":\"石子儿\"}", tempStudent);

             Console.Read();
         }

     }

     /// <summary>
     /// 学生信息实体
     /// </summary>
     public class Student
     {
         public int ID { get; set; }
         public string Name { get; set; }
         public string NickName { get; set; }
         public Class Class { get; set; }
     }

     /// <summary>
     /// 学生班级实体
     /// </summary>
     public class Class
     {
         public int ID { get; set; }
         public string Name { get; set; }
     }

使用Json帮助类时，有两点需要注意下：

1. 通常使用调用实体序列化SerializeObject()和反序列化DeserializeJsonToObject()两个方法就可以了。但有些情况下我们解析json字符串时，可能没有对应的实体类型（或者说不想添加对应的实体类），这时候可以用匿名对象解析方法DeserializeAnonymousType()，方便快捷，对应代码如下：

  //匿名对象解析
             var tempEntity = new { ID = , Name = string.Empty };
             string json5 = JsonHelper.SerializeObject(tempEntity);
             //json5 : {"ID":0,"Name":""}
             tempEntity = JsonHelper.DeserializeAnonymousType("{\"ID\":\"112\",\"Name\":\"石子儿\"}", tempEntity);
             Console.WriteLine(tempEntity.ID + ":" + tempEntity.Name);

2. Json的两种结构数组和对象解析时略有不同。Json对象一般转换成实体，Json数组一般转换成实体集合。代码如下：

 //验证对象和数组
             Student sdudent4 = JsonHelper.DeserializeJsonToObject<Student>("{\"ID\":\"112\",\"Name\":\"石子儿\"}");
             List<Student> sdudentList4 = JsonHelper.DeserializeJsonToList<Student>("[{\"ID\":\"112\",\"Name\":\"石子儿\"}]");

简单解释下Json对象和数组的含义：

对象是以“{”（左括号）开始，“}”（右括号）结束。每个“名称”后跟一个“:”（冒号）；“‘名称/值’ 对”之间运用 “,”（逗号）分隔。名称用引号括起来；值如果是字符串则必须用括号，数值型则不须要。例如：{"ID":"112","Name":"石子儿"}。

数组是值（value）的有序集合。一个数组以“[”（左中括号）开始，“]”（右中括号）结束。值之间运用 “,”（逗号）分隔。例如：[{"ID":"112","Name":"石子儿"},{"ID":"113","Name":"陈晨"}]。

备注： //JavaScriptArray--->  JArray
          //JavaScriptConvert--->JsonConvert  
          //JavaScriptObject--->JObject

资源下载：Json90r1