LitJSON之JSON与对象间的相互映射

快速入门

JSON与对象间的相互映射

为了能在.NET程序中使用JSON格式的数据，我们首先能想到的方法是使用JSON文本去填充特定类别的新实例；或者用一种传统的方法去构建与输入的JSON文本相对应的数据结构，再或者用创建字典这种更为普遍的方法。
相反，一个简单的输出操作可能更加适合，使用对象中存储的数据来生成新的JSON字符串。
基于这种目的，litjson中包含了一个jsonmapper类，该类别为实现json到对象和对象到json转化提供了两种主要方法：JsonMapper.ToObject 和 JsonMapper.ToJson.

简单的JsonMapper 案例

如下列案例所示，ToObject 中有一个“JsonMapper.ToObject”的重载方法，可以用来指定返回的对象类型。

using LitJson;using System;public class Person{    // C# 3.0 auto-implemented properties    public string   Name     { get; set; }    public int      Age      { get; set; }    public DateTime Birthday { get; set; }}public class JsonSample{    public static void Main()    {        PersonToJson();        JsonToPerson();    }    public static void PersonToJson()    {        Person bill = new Person();        bill.Name = "William Shakespeare";        bill.Age  = 51;        bill.Birthday = new DateTime(1564, 4, 26);        string json_bill = JsonMapper.ToJson(bill);        Console.WriteLine(json_bill);    }    public static void JsonToPerson()    {        string json = @"            {                ""Name""     : ""Thomas More"",                ""Age""      : 57,                ""Birthday"" : ""02/07/1478 00:00:00""            }";        Person thomas = JsonMapper.ToObject<Person>(json);        Console.WriteLine("Thomas' age: {0}", thomas.Age);    }}

案例输出：

{"Name":"William Shakespeare","Age":51,"Birthday":"04/26/1564 00:00:00"}Thomas' age: 57

使用不带类型的JsonMapper.ToObject

当JSON文件将被读取，而与对应数据结构相匹配的类并不可用或者格式不对时，用户可以使用不带类型的toobject方法。该方法返回一个JsonData实例。JsonData 是一个通用的目标格式，它支持包括链表和字典在内所有的JSON的数据格式。

using LitJson;using System;public class JsonSample{    public static void Main()    {        string json = @"          {            ""album"" : {              ""name""   : ""The Dark Side of the Moon"",              ""artist"" : ""Pink Floyd"",              ""year""   : 1973,              ""tracks"" : [                ""Speak To Me"",                ""Breathe"",                ""On The Run""              ]            }          }        ";        LoadAlbumData(json);    }    public static void LoadAlbumData(string json_text)    {        Console.WriteLine("Reading data from the following JSON string: {0}",                          json_text);        JsonData data = JsonMapper.ToObject(json_text);        // Dictionaries are accessed like a hash-table        Console.WriteLine("Album's name: {0}", data["album"]["name"]);        // Scalar elements stored in a JsonData instance can be cast to        // their natural types        string artist = (string) data["album"]["artist"];        int    year   = (int) data["album"]["year"];        Console.WriteLine("Recorded by {0} in {1}", artist, year);        // Arrays are accessed like regular lists as well        Console.WriteLine("First track: {0}", data["album"]["tracks"][0]);    }}

案例输出：

Reading data from the following JSON string:          {            "album" : {              "name"   : "The Dark Side of the Moon",              "artist" : "Pink Floyd",              "year"   : 1973,              "tracks" : [                "Speak To Me",                "Breathe",                "On The Run"              ]            }          }Album's name: The Dark Side of the MoonRecorded by Pink Floyd in 1973First track: Speak To Me

目录

• 介绍
• 快速开始
  
  • 将JSON与Object相互映射
  • JSON的读取和写入
  • 配置库