Newtonsoft.Json(Json.Net)學習筆記，newtonsoft.json
Newtonsoft.Json，一款.NET中開源的Json序列化和反序列化類庫(下載地址http://json.codeplex.com/)。
下面是Json序列化和反序列化的簡單封裝：
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/// <summary>
/// Json幫助類
/// </summary>
public class JsonHelper
{
/// <summary>
/// 將對象序列化為JSON格式
/// </summary>
/// <param name="o">對象</param>
/// <returns>json字符串</returns>
public static string SerializeObject(object o)
{
string json = JsonConvert.SerializeObject(o);
return json;
}
/// <summary>
/// 解析JSON字符串生成對象實體
/// </summary>
/// <typeparam name="T">對象類型</typeparam>
/// <param name="json">json字符串(eg.{"ID":"112","Name":"石子兒"})</param>
/// <returns>對象實體</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數組生成對象實體集合
/// </summary>
/// <typeparam name="T">對象類型</typeparam>
/// <param name="json">json數組字符串(eg.[{"ID":"112","Name":"石子兒"}])</param>
/// <returns>對象實體集合</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到給定的匿名對象.
/// </summary>
/// <typeparam name="T">匿名對象類型</typeparam>
/// <param name="json">json字符串</param>
/// <param name="anonymousTypeObject">匿名對象</param>
/// <returns>匿名對象</returns>
public static T DeserializeAnonymousType<T>(string json, T anonymousTypeObject)
{
T t = JsonConvert.DeserializeAnonymousType(json, anonymousTypeObject);
return t;
}
}
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為進一步理解Newtonsoft，寫了一些測試的例子：
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/// <summary>
/// Json測試
/// </summary>
public class JsonTest : IRun
{
public void Run()
{
Student sdudent = new Student();
sdudent.ID = 1;
sdudent.Name = "陳晨";
sdudent.NickName = "石子兒";
sdudent.Class = new Class() { Name = "CS0216", ID = 0216 };
//實體序列化和反序列化
string json1 = JsonHelper.SerializeObject(sdudent);
//json1 : {"ID":1,"Name":"陳晨","NickName":"石子兒","Class":{"ID":216,"Name":"CS0216"}}
Student sdudent1 = JsonHelper.DeserializeJsonToObject<Student>(json1);
//實體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":"陳晨","NickName":"石子兒","Class":{"ID":216,"Name":"CS0216"}},{"ID":1,"Name":"陳晨","NickName":"石子兒","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"] = 112;
dr["Name"] = "戰三";
dr["NickName"] = "小三";
dt.Rows.Add(dr);
string json3 = JsonHelper.SerializeObject(dt);
//json3 : [{"ID":112,"Name":"戰三","NickName":"小三"}]
DataTable sdudentDt3 = JsonHelper.DeserializeJsonToObject<DataTable>(json3);
List<Student> sdudentList3 = JsonHelper.DeserializeJsonToList<Student>(json3);
//驗證對象和數組
Student sdudent4 = JsonHelper.DeserializeJsonToObject<Student>("{\"ID\":\"112\",\"Name\":\"石子兒\"}");
List<Student> sdudentList4 = JsonHelper.DeserializeJsonToList<Student>("[{\"ID\":\"112\",\"Name\":\"石子兒\"}]");
//匿名對象解析
var tempEntity = new { ID = 0, Name = string.Empty };
string json5 = JsonHelper.SerializeObject(tempEntity);
//json5 : {"ID":0,"Name":""}
tempEntity = JsonHelper.DeserializeAnonymousType("{\"ID\":\"112\",\"Name\":\"石子兒\"}", tempEntity);
var tempStudent = new Student();
tempStudent = JsonHelper.DeserializeAnonymousType("{\"ID\":\"112\",\"Name\":\"石子兒\"}", tempStudent);
Console.Read();
}
}
/// <summary>
/// 學生信息實體
/// </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>
/// 學生班級實體
/// </summary>
public class Class
{
public int ID { get; set; }
public string Name { get; set; }
}
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使用Json幫助類時，有兩點需要注意下：
1. 通常使用調用實體序列化SerializeObject()和反序列化DeserializeJsonToObject()兩個方法就可以了。但有些情況下我們解析json字符串時，可能沒有對應的實體類型（或者說不想添加對應的實體類），這時候可以用匿名對象解析方法DeserializeAnonymousType()，方便快捷，對應代碼如下：
//匿名對象解析
var tempEntity = new { ID = 0, Name = string.Empty };
string json5 = JsonHelper.SerializeObject(tempEntity);
//json5 : {"ID":0,"Name":""}
tempEntity = JsonHelper.DeserializeAnonymousType("{\"ID\":\"112\",\"Name\":\"石子兒\"}", tempEntity);
Console.WriteLine(tempEntity.ID + ":" + tempEntity.Name);
2. Json的兩種結構數組和對象解析時略有不同。Json對象一般轉換成實體，Json數組一般轉換成實體集合。代碼如下：
//驗證對象和數組
Student sdudent4 = JsonHelper.DeserializeJsonToObject<Student>("{\"ID\":\"112\",\"Name\":\"石子兒\"}");
List<Student> sdudentList4 = JsonHelper.DeserializeJsonToList<Student>("[{\"ID\":\"112\",\"Name\":\"石子兒\"}]");
簡單解釋下Json對象和數組的含義：
對象是以“{”（左括號）開始，“}”（右括號）結束。每個“名稱”後跟一個“:”（冒號）；“‘名稱/值’ 對”之間運用 “,”（逗號）分隔。名稱用引號括起來；值如果是字符串則必須用括號，數值型則不須要。例如：{"ID":"112","Name":"石子兒"}。
數組是值（value）的有序集合。一個數組以“[”（左中括號）開始，“]”（右中括號）結束。值之間運用 “,”（逗號）分隔。例如：[{"ID":"112","Name":"石子兒"},{"ID":"113","Name":"陳晨"}]。
