.Net使用Newtonsoft.Json.dll(JSON.NET)对象序列化成json、反序列化json示例教程

JSON作为一种轻量级的数据交换格式，简单灵活，被很多系统用来数据交互，作为一名.NET开发人员，JSON.NET无疑是最好的序列化框架，支持XML和JSON序列化，高性能，免费开源，支持LINQ查询。目前已被微软集成于webapi框架之中，因此，熟练掌握JSON.NET相当重要，这篇文章是零度参考官网整理的示例，通过这些示例，可以全面了解JSON.NET提供的功能。

Newtonsoft.Json的地址：

官网：http://json.codeplex.com/

源码地址：https://github.com/JamesNK/Newtonsoft.Json

Newtonsoft.Json.dll下载：https://github.com/JamesNK/Newtonsoft.Json/releases

1、使用Newtonsoft.Json(JSON.NET)序列化对象,通过Newtonsoft.Json.Formatting将json格式化输出。

Account account = new Account
{
Email = "1930906722@qq.com",
Active = true,
CreatedDate =DateTime.Now,
Roles = new List<string> { "User", "Admin" }
};
string json = Newtonsoft.Json.JsonConvert.SerializeObject(account, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

public class Account
{
public string Name { get; set; }
public string Email { get; set; }
public bool Active { get; set; }
public DateTime CreatedDate { get; set; }
public IList<string> Roles { get; set; }
}

执行结果：



2、使用Newtonsoft.Json(JSON.NET)序列化List集合：

List<string> videogames = new List<string> { "HTML5", "JavaScript", ".net","c#",".net core" };
string json = Newtonsoft.Json.JsonConvert.SerializeObject(videogames);
Console.WriteLine(json);

执行结果：



3、使用Newtonsoft.Json(JSON.NET)序列化dictionary字典

System.Collections.Generic.Dictionary<string, string> dic = new System.Collections.Generic.Dictionary<string, string>
{
{ "Name", "张三" },
{ "Age", "20" },
{ "Email", "193090622@qq.com" }
};
string json1 = Newtonsoft.Json.JsonConvert.SerializeObject(dic, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json1);
Console.WriteLine("");
Console.WriteLine("未格式化的json：");
string json2 = Newtonsoft.Json.JsonConvert.SerializeObject(dic, Newtonsoft.Json.Formatting.None);
Console.WriteLine(json2);

执行结果：



4、Newtonsoft.Json(JSON.NET)将序列化结果保存到指定的文件：

User movie = new User { Name = "张三", Age = 1993 };
using (System.IO.StreamWriter file = System.IO.File.CreateText(@"F:\UserInfo.txt"))
{
Newtonsoft.Json.JsonSerializer serializer = new Newtonsoft.Json.JsonSerializer();
serializer.Serialize(file, movie);
}

public class User
{
public string Name { set; get; }
public int Age { set; get; }
}

执行后保存到文件的结果：



5、Newtonsoft.Json(JSON.NET)基于枚举类型的JsonConverters转换器

List<JosnEnum> list = new List<JosnEnum> { JosnEnum.NotStartus, JosnEnum.Startus };
string json = Newtonsoft.Json.JsonConvert.SerializeObject(list);
Console.WriteLine(json);
Console.WriteLine("");

System.Collections.Generic.Dictionary<string, int> dic = new System.Collections.Generic.Dictionary<string, int>
{
{((JosnEnum)(int)JosnEnum.NotStartus).ToString() ,(int)JosnEnum.NotStartus} ,
{((JosnEnum)(int)JosnEnum.Startus).ToString() ,(int)JosnEnum.Startus}
};
string dicJson = Newtonsoft.Json.JsonConvert.SerializeObject(dic);
Console.WriteLine(dicJson);

Console.WriteLine("");
List<JosnEnum> list2 = new List<JosnEnum>
{
JosnEnum.NotStartus,
JosnEnum.Startus
};
string json3 = Newtonsoft.Json.JsonConvert.SerializeObject(list2, new Newtonsoft.Json.Converters.StringEnumConverter());
Console.WriteLine(json3);

Console.WriteLine("");

List<JosnEnum> result = Newtonsoft.Json.JsonConvert.DeserializeObject<List<JosnEnum>>(json3, new Newtonsoft.Json.Converters.StringEnumConverter());
Console.WriteLine(string.Join(", ", result.Select(c => c.ToString())));

public enum JosnEnum
{
NotStartus = 0,
Startus = 1
}

执行结果：



6、Newtonsoft.Json(JSON.NET)通过JRaw将JS函数序列化到JSON中

JavaScriptSettings settings = new JavaScriptSettings
{
OnLoadFunction = new Newtonsoft.Json.Linq.JRaw("OnLoad"),
OnSucceedFunction = new Newtonsoft.Json.Linq.JRaw("function(e) { alert(e); }")
};
string json = Newtonsoft.Json.JsonConvert.SerializeObject(settings, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

public class JavaScriptSettings
{
public Newtonsoft.Json.Linq.JRaw OnLoadFunction { get; set; }
public Newtonsoft.Json.Linq.JRaw OnSucceedFunction { get; set; }
}

7、使用Newtonsoft.Json(JSON.NET)将json反序列化对象

string json = @"{
'Email': '1930906722@qq.com',
'Active': true,
'CreatedDate': '2016-11-26 20:39',
'Roles': [
'User',
'Admin'
]
}";
Account account = Newtonsoft.Json.JsonConvert.DeserializeObject<Account>(json);
Console.WriteLine(account.Email);

public class Account
{
public string Name { get; set; }
public string Email { get; set; }
public bool Active { get; set; }
public DateTime CreatedDate { get; set; }
public IList<string> Roles { get; set; }
}

执行结果：



8、使用Newtonsoft.Json(JSON.NET)反序列化List集合：

string json = @"['Html5','C#','.Net','.Net Core']";
List<string> videogames = Newtonsoft.Json.JsonConvert.DeserializeObject<List<string>>(json);
Console.WriteLine(string.Join(", ", videogames));

执行结果：



9、使用Newtonsoft.Json(JSON.NET)反序列化dictionary字典

string json = @"{'Name': '张三','Age': '23'}";
var htmlAttributes = Newtonsoft.Json.JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
Console.WriteLine(htmlAttributes["Name"]);
Console.WriteLine(htmlAttributes["Age"]);

执行结果：



10、使用Newtonsoft.Json(JSON.NET)序列化var匿名类型，有时候，我们并不需要先定义一个类，然后new一个对象后再进行序列化，JSON.NET支持匿名类型的序列化和反序列化。

var test1 = new { Name = "李四", Age = 26 };
var json = Newtonsoft.Json.JsonConvert.SerializeObject(test1);
Console.WriteLine(json);

Console.WriteLine("");
var test2 = new { Name = "", Age = 0 };
string json1 = @"{'Name':'张三','Age':'25'}";
var result = Newtonsoft.Json.JsonConvert.DeserializeAnonymousType(json1, test2);
Console.WriteLine(result.Name);

执行结果：



11、Newtonsoft.Json(JSON.NET)用新JSON字符串填充指定对象的属性值

Account account = new Account
{
Email = "1930906722@qq.com",
Active = true,
CreatedDate = DateTime.Now,
Roles = new List<string> { "User", "Admin" }
};
string json = @"{'Active': false, 'Roles': ['Expired']}";
Newtonsoft.Json.JsonConvert.PopulateObject(json, account);
Console.WriteLine(account.Active);
Console.WriteLine(account.Email);

public class Account
{
public string Name { get; set; }
public string Email { get; set; }
public bool Active { get; set; }
public DateTime CreatedDate { get; set; }
public IList<string> Roles { get; set; }
}

执行结果：



12、使用Newtonsoft.Json(JSON.NET)反序列化时可指定构造函数：

首先我们定义如下的类型，我们希望JSON.NET反序列化对象时使用第2个构造函数，我们将第一个默认构造函数屏蔽，标记为私有private修饰符。第2个构造函数需要指定一个website对象作为参数，如果提供的参数为null则抛出异常：

public class Website
{
public string Url { get; set; }
private Website()
{
}
public Website(Website website)
{
if (website == null) throw new ArgumentNullException("website");
Url = website.Url;
}
}

现在使用一般的方式反序列化一个JSON字符串。执行出现的结果：



我们发现该序列化方法抛出了异常，并没有按照我们预想的方式进行反序列化，JSON.NET提供如下的方式指定公有构造函数。

string json = @"{'Url':'http://www.cnblogs.com/linJie1930906722/'}";
Website website = Newtonsoft.Json.JsonConvert.DeserializeObject<Website>(json, new Newtonsoft.Json.JsonSerializerSettings
{
ConstructorHandling = Newtonsoft.Json.ConstructorHandling.AllowNonPublicDefaultConstructor
});
Console.WriteLine(website.Url);

执行结果：



另外，JSON.NET提供了指定任何构造函数的JsonConstructorAttribute特性，只需要在构造函数上标记，即可指定构造函数。

public class Users
{
public string UserName { get; private set; }
public bool Enabled { get; private set; }
public Users()
{
}
[Newtonsoft.Json.JsonConstructor]
public Users(string userName, bool enabled)
{
UserName = userName;
Enabled = enabled;
}
}

string json = @"{""UserName"": ""希特勒"",""Enabled"": true}";
Users user = Newtonsoft.Json.JsonConvert.DeserializeObject<Users>(json);
Console.WriteLine(user.UserName);

执行结果：



13、当对象的属性为默认值(0或null)时不序列化该属性

public class Person
{
public string Name { get; set; }
public int Age { get; set; }
public Person Partner { get; set; }
public decimal? Salary { get; set; }
}

Person person1 = new Person();
string json1 = Newtonsoft.Json.JsonConvert.SerializeObject(person1, Newtonsoft.Json.Formatting.Indented, new Newtonsoft.Json.JsonSerializerSettings
{
DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Ignore
});
Console.WriteLine(json1);

Console.WriteLine("");
Person person2 = new Person(){Name = "奥巴马"};
string json2 = Newtonsoft.Json.JsonConvert.SerializeObject(person2, Newtonsoft.Json.Formatting.Indented, new Newtonsoft.Json.JsonSerializerSettings
{
DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Ignore
});
Console.WriteLine(json2);

执行结果：



14、Newtonsoft.Json（JSON.NET）中忽略null值得处理器

public class Person
{
public string Name { get; set; }
public int Age { get; set; }
public Person Partner { get; set; }
public decimal? Salary { get; set; }
}

Person person = new Person { Name = "张三", Age = 46 };
string jsonIncludeNullValues = Newtonsoft.Json.JsonConvert.SerializeObject(person, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(jsonIncludeNullValues);
Console.WriteLine("");
string json = Newtonsoft.Json.JsonConvert.SerializeObject(person, Newtonsoft.Json.Formatting.Indented, new Newtonsoft.Json.JsonSerializerSettings
{
NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore
});
Console.WriteLine(json);

执行结果：



15、JSON.NET中循环引用的处理方法

Employee employee1 = new Employee { Name = "张三" };
Employee employee2 = new Employee { Name = "李四" };
employee1.Manager = employee2;
employee2.Manager = employee2;
string json = Newtonsoft.Json.JsonConvert.SerializeObject(employee1, Newtonsoft.Json.Formatting.Indented, new Newtonsoft.Json.JsonSerializerSettings
{
ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore
});
Console.WriteLine(json);

public class Employee
{
public string Name { get; set; }
public Employee Manager { get; set; }
}

执行结果：



16、通过ContractResolver指定属性名首字母小写，通常，在.NET中属性采用PascalCase规则（首字母大写），在JavaScript中属性名使用CamelCase规则（首字母小写），我们希望序列化后的JSON字符串符合CamelCase规则，JSON.NET提供的ContractResolver可以设置属性名小写序列化

public class User
{
public string Name { set; get; }
public int Age { set; get; }
}

User person = new User { Name = "张三", Age =52 };
string json = Newtonsoft.Json.JsonConvert.SerializeObject(person, Newtonsoft.Json.Formatting.Indented, new Newtonsoft.Json.JsonSerializerSettings
{
ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
});
Console.WriteLine(json);

执行结果：



17、JSON.NET中通过特性序列化枚举类型

public enum ProductStatus
{
NotConfirmed,
Active, Deleted
}

public class Product
{
public string Name { get; set; }

[Newtonsoft.Json.JsonConverter(typeof(Newtonsoft.Json.Converters.StringEnumConverter))]
public ProductStatus Status { get; set; }
}

Product user = new Product { Name = @"羽绒服", Status = ProductStatus.Deleted };
string json = Newtonsoft.Json.JsonConvert.SerializeObject(user, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

执行结果：



18、指定需要序列化的属性

[Newtonsoft.Json.JsonObject(Newtonsoft.Json.MemberSerialization.OptIn)]
public class Categroy
{
//Id不需要序列化
public Guid Id { get; set; }

[Newtonsoft.Json.JsonProperty]
public string Name { get; set; }

[Newtonsoft.Json.JsonProperty]
public int Size { get; set; }
}

Categroy categroy = new Categroy
{
Id = Guid.NewGuid(),
Name = "内衣",
Size = 52
};
string json = Newtonsoft.Json.JsonConvert.SerializeObject(categroy, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

执行结果：



19、序列化对象时指定属性名

public class Videogame
{
[Newtonsoft.Json.JsonProperty("name")]
public string Name { get; set; }

[Newtonsoft.Json.JsonProperty("release_date")]
public DateTime ReleaseDate { get; set; }
}

Videogame starcraft = new Videogame
{
Name = "英雄联盟",
ReleaseDate = DateTime.Now
};
string json = Newtonsoft.Json.JsonConvert.SerializeObject(starcraft, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

执行结果：



20、序列化时指定属性在JSON中的顺序

public class Personl
{
[Newtonsoft.Json.JsonProperty(Order = 2)]
public string FirstName { get; set; }

[Newtonsoft.Json.JsonProperty(Order = 1)]
public string LastName { get; set; }
}

Personl person = new Personl { FirstName = "张三", LastName = "李四" };
string json = Newtonsoft.Json.JsonConvert.SerializeObject(person, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

执行结果：



21、反序列化指定属性是否必须有值必须不为null，在反序列化一个JSON时，可通过JsonProperty特性的Required指定反序列化行为，当反序列化行为与指定的行为不匹配时，JSON.NET将抛出异常，Required是枚举，Required.Always表示属性必须有值切不能为null，Required.AllowNull表示属性必须有值，但允许为null值。

public class Order
{
[Newtonsoft.Json.JsonProperty(Required = Newtonsoft.Json.Required.Always)]
public string Name { get; set; }

[Newtonsoft.Json.JsonProperty(Required = Newtonsoft.Json.Required.AllowNull)]
public DateTime? ReleaseDate { get; set; }
}

string json = @"{
'Name': '促销订单',
'ReleaseDate': null
}";
Order order = Newtonsoft.Json.JsonConvert.DeserializeObject<Order>(json);
Console.WriteLine(order.Name);
Console.WriteLine(order.ReleaseDate);

执行结果：



22、通过特性指定null值忽略序列化

public class Vessel
{
public string Name { get; set; }

[Newtonsoft.Json.JsonProperty(NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
public DateTime? LaunchDate { get; set; }
}

Vessel vessel = new Vessel { Name = "张三" };
string json = Newtonsoft.Json.JsonConvert.SerializeObject(vessel, Newtonsoft.Json.Formatting.Indented);
Console.WriteLine(json);

执行结果：



23、忽略不需要序列化的属性，并不是对象所有属性都要参与序列化，我们可以使用JsonIgnore特性排除不需要序列化的属性，下面示例中的PasswordHash将被忽略。

public class Accounts
{
public string FullName { get; set; }
public string EmailAddress { get; set; }
[Newtonsoft.Json.JsonIgnore]
public string PasswordHash { get; set; }
}

Accounts account = new Accounts
{
FullName = "admin",
EmailAddress = "1930906722@qq.com",
PasswordHash = "dfsfgerhtyhsasdhjyujtgwe454811sfsg8d"
};
string json = Newtonsoft.Json.JsonConvert.SerializeObject(account);
Console.WriteLine(json);

执行结果：



24、序列化或反序列化时指定日期时间格式，JSON.NET中提供一个名为JsonSerializerSettings的设置对象，可通过此对象设置很多序列化和反序列化的行为，如果要设置JSON.NET序列化输出的日期时间格式，只需要指定格式化字符串即可。通过JsonSerializerSettings的DateFormatString属性指定日期时间格式：

public class Customer
{
public string FirstName { get; set; }
public string LastName { get; set; }
public DateTime CreateDate { get; set; }
}

Customer custom = new Customer { FirstName = "张三", LastName = "李四", CreateDate = DateTime.Now };
Newtonsoft.Json.JsonSerializerSettings settings = new Newtonsoft.Json.JsonSerializerSettings
{
DateFormatString = "yyyy-MM-dd HH:mm:ss",
Formatting = Newtonsoft.Json.Formatting.Indented
};
string json = Newtonsoft.Json.JsonConvert.SerializeObject(custom, settings);
Console.WriteLine(json);

执行结果：