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

Posted 2020-08-21 赛跑的蜗牛

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 = "[e-mail]",
                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", "[e-mail]" }
            };
            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\': \'[e-mail]\',
   \'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 = "[e-mail]",
                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 = "[e-mail]",
                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：