Json.NET Documentation -- 摘录

网址：https://www.newtonsoft.com/json/help/html/Samples.htm

目录：

Samples

• Serializing JSON - 序列化和反序列化 JSON、序列化器设置和序列化属性
• LINQ to JSON - 解析、查询、修改和编写 JSON
• JSON Schema - 加载模式并验证 JSON。请注意，JSON 模式验证已移至其自己的包中。有关 更多详细信息，请参阅https://www.newtonsoft.com/jsonschema。
• 转换 XML - 将 JSON 转换为 XML 和将 XML转换为 JSON
• BSON - 序列化和反序列化 BSON
• 读取和写入 JSON - 使用 JsonTextReader 读取 JSON，使用 JsonTextWriter 写入 JSON

Serializing JSON

序列化对象

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

Account account = new Account
{
    Email = "james@example.com",
    Active = true,
    CreatedDate = new DateTime(2013, 1, 20, 0, 0, 0, DateTimeKind.Utc),
    Roles = new List
    {
        "User",
        "Admin"
    }
};

string json = JsonConvert.SerializeObject(account, Formatting.Indented);
// {
//   "Email": "james@example.com",
//   "Active": true,
//   "CreatedDate": "2013-01-20T00:00:00Z",
//   "Roles": [
//     "User",
//     "Admin"
//   ]
// }

Console.WriteLine(json);

序列化字典

Dictionary points = new Dictionary
{
    { "James", 9001 },
    { "Jo", 3474 },
    { "Jess", 11926 }
};

string json = JsonConvert.SerializeObject(points, Formatting.Indented);

Console.WriteLine(json);
// {
//   "James": 9001,
//   "Jo": 3474,
//   "Jess": 11926
// }

序列化集合

List videogames = new List
{
    "Starcraft",
    "Halo",
    "Legend of Zelda"
};

string json = JsonConvert.SerializeObject(videogames);

Console.WriteLine(json);
// ["Starcraft","Halo","Legend of Zelda"]

将 JSON 序列化为文件

public class Movie
{
    public string Name { get; set; }
    public int Year { get; set; }
}

Movie movie = new Movie
{
    Name = "Bad Boys",
    Year = 1995
};

// serialize JSON to a string and then write string to a file
File.WriteAllText(@"c:\movie.json", JsonConvert.SerializeObject(movie));

// serialize JSON directly to a file
using (StreamWriter file = File.CreateText(@"c:\movie.json"))
{
    JsonSerializer serializer = new JsonSerializer();
    serializer.Serialize(file, movie);
}

Deserialize to JSON

反序列化对象

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

string json = @"{
  'Email': 'james@example.com',
  'Active': true,
  'CreatedDate': '2013-01-20T00:00:00Z',
  'Roles': [
    'User',
    'Admin'
  ]
}";

Account account = JsonConvert.DeserializeObject(json);

Console.WriteLine(account.Email);
// james@example.com

反序列化集合

string json = @"['Starcraft','Halo','Legend of Zelda']";List videogames = JsonConvert.DeserializeObject>(json);Console.WriteLine(string.Join(", ", videogames.ToArray()));// Starcraft, Halo, Legend of Zelda

序列化字典

string json = @"{
  'href': '/account/login.aspx',
  'target': '_blank'
}";

Dictionary htmlAttributes = JsonConvert.DeserializeObject>(json);

Console.WriteLine(htmlAttributes["href"]);
// /account/login.aspx

Console.WriteLine(htmlAttributes["target"]);
// _blank

反序列化匿名类型

var definition = new { Name = "" };

string json1 = @"{'Name':'James'}";
var customer1 = JsonConvert.DeserializeAnonymousType(json1, definition);

Console.WriteLine(customer1.Name);
// James

string json2 = @"{'Name':'Mike'}";
var customer2 = JsonConvert.DeserializeAnonymousType(json2, definition);

Console.WriteLine(customer2.Name);
// Mike

从文件反序列化 JSON

{
    public string Name { get; set; }
    public int Year { get; set; }
}

// read file into a string and deserialize JSON to a type
Movie movie1 = JsonConvert.DeserializeObject(File.ReadAllText(@"c:\movie.json"));

// deserialize JSON directly from a file
using (StreamReader file = File.OpenText(@"c:\movie.json"))
{
    JsonSerializer serializer = new JsonSerializer();
    Movie movie2 = (Movie)serializer.Deserialize(file, typeof(Movie));
}

Convert JSON to XML

将 JSON 转换为 XML

string json = @"{
  '@Id': 1,
  'Email': 'james@example.com',
  'Active': true,
  'CreatedDate': '2013-01-20T00:00:00Z',
  'Roles': [
    'User',
    'Admin'
  ],
  'Team': {
    '@Id': 2,
    'Name': 'Software Developers',
    'Description': 'Creators of fine software products and services.'
  }
}";

XNode node = JsonConvert.DeserializeXNode(json, "Root");

Console.WriteLine(node.ToString());
// 
//   james@example.com
//   true
//   2013-01-20T00:00:00Z
//   User
//   Admin
//   
//     Software Developers
//     Creators of fine software products and services.
//   
// 

将XML 转换为JSON

string xml = @"<?xml version='1.0' standalone='no'?>

  
  Alan
  http://www.google.com
  
  
  Louis
  http://www.yahoo.com
  
";

XmlDocument doc = new XmlDocument();
doc.LoadXml(xml);

string json = JsonConvert.SerializeXmlNode(doc);

Console.WriteLine(json);
// {
//   "?xml": {
//     "@version": "1.0",
//     "@standalone": "no"
//   },
//   "root": {
//     "person": [
//       {
//         "@id": "1",
//         "name": "Alan",
//         "url": "http://www.google.com"
//       },
//       {
//         "@id": "2",
//         "name": "Louis",
//         "url": "http://www.yahoo.com"
//       }
//     ]
//   }
// }

LINQ to JSON

手动创建 JSON

JArray array = new JArray();
array.Add("Manual text");
array.Add(new DateTime(2000, 5, 23));

JObject o = new JObject();
o["MyArray"] = array;

string json = o.ToString();
// {
//   "MyArray": [
//     "Manual text",
//     "2000-05-23T00:00:00"
//   ]
// }

使用集合创建 JSON

JObject o = new JObject
{
    { "Cpu", "Intel" },
    { "Memory", 32 },
    {
        "Drives", new JArray
        {
            "DVD",
            "SSD"
        }
    }
};

Console.WriteLine(o.ToString());
// {
//   "Cpu": "Intel",
//   "Memory": 32,
//   "Drives": [
//     "DVD",
//     "SSD"
//   ]
// }

使用 JTokenWriter 创建 JSON

JTokenWriter writer = new JTokenWriter();
writer.WriteStartObject();
writer.WritePropertyName("name1");
writer.WriteValue("value1");
writer.WritePropertyName("name2");
writer.WriteStartArray();
writer.WriteValue(1);
writer.WriteValue(2);
writer.WriteEndArray();
writer.WriteEndObject();

JObject o = (JObject)writer.Token;

Console.WriteLine(o.ToString());
// {
//   "name1": "value1",
//   "name2": [
//     1,
//     2
//   ]
// }

从对象创建 JSON

Computer computer = new Computer
{
    Cpu = "Intel",
    Memory = 32,
    Drives = new List
    {
        "DVD",
        "SSD"
    }
};

JObject o = (JObject)JToken.FromObject(computer);

Console.WriteLine(o.ToString());
// {
//   "Cpu": "Intel",
//   "Memory": 32,
//   "Drives": [
//     "DVD",
//     "SSD"
//   ]
// }

JArray a = (JArray)JToken.FromObject(computer.Drives);

Console.WriteLine(a.ToString());
// [
//   "DVD",
//   "SSD"
// ]

public class Computer
{
    public string Cpu { get; set; }
    public int Memory { get; set; }
    public IList Drives { get; set; }
}

使用 JObject.Parse 解析 JSON 对象

string json = @"{
  CPU: 'Intel',
  Drives: [
    'DVD read/writer',
    '500 gigabyte hard drive'
  ]
}";

JObject o = JObject.Parse(json);

Console.WriteLine(o.ToString());
// {
//   "CPU": "Intel",
//   "Drives": [
//     "DVD read/writer",
//     "500 gigabyte hard drive"
//   ]
// }

从文件中读取 JSON

JObject o1 = JObject.Parse(File.ReadAllText(@"c:\videogames.json"));

// read JSON directly from a file
using (StreamReader file = File.OpenText(@"c:\videogames.json"))
using (JsonTextReader reader = new JsonTextReader(file))
{
    JObject o2 = (JObject)JToken.ReadFrom(reader);
}

将 JSON 写入文件

JObject videogameRatings = new JObject(
     new JProperty( "Halo" , 9 ),
     new JProperty( "Starcraft" , 9 ),
     new JProperty( "Call of Duty" , 7.5 ));

File.WriteAllText( @"c:\videogames.json" , videogameRatings.ToString());

// 将 JSON 直接写入文件
using (StreamWriter file = File.CreateText( @"c:\videogames.json" ))
 using (JsonTextWriter writer = new JsonTextWriter(file))
{
    videogameRatings.WriteTo(writer);
}

将 JSON 转换为集合

string json = @"{
  'd': [
    {
      'Name': 'John Smith'
    },
    {
      'Name': 'Mike Smith'
    }
  ]
}";

JObject o = JObject.Parse(json);

JArray a = (JArray)o["d"];

IList person = a.ToObject>();

Console.WriteLine(person[0].Name);
// John Smith

Console.WriteLine(person[1].Name);
// Mike Smith

使用 JObject.Properties

JObject o = new JObject
{
    { "name1", "value1" },
    { "name2", "value2" }
};

foreach (JProperty property in o.Properties())
{
    Console.WriteLine(property.Name + " - " + property.Value);
}
// name1 - value1
// name2 - value2

foreach (KeyValuePair property in o)
{
    Console.WriteLine(property.Key + " - " + property.Value);
}
// name1 - value1
// name2 - value2

使用 JToken.ToString 写入 JSON 文本

JObject o = JObject.Parse( @"{'string1':'value','integer2':99,'datetime3':'2000-05-23T00:00:00'}" );

Console.WriteLine(o.ToString());
// { 
// "string1": "value", 
// "integer2": 99, 
// "datetime3": "2000-05-23T00:00:00" 
// }

Console.WriteLine(o.ToString(Formatting.None));
// {"string1":"value","integer2":99,"datetime3":"2000-05-23T00:00:00"}

Console.WriteLine(o.ToString(Formatting.None, new JavaScriptDateTimeConverter()));
// {"string1":"value","integer2":99,"datetime3":new Date(959032800000)}

JSON Path

使用 JSON 路径查询 JSON

JObject o = JObject.Parse(@"{
  'Stores': [
    'Lambton Quay',
    'Willis Street'
  ],
  'Manufacturers': [
    {
      'Name': 'Acme Co',
      'Products': [
        {
          'Name': 'Anvil',
          'Price': 50
        }
      ]
    },
    {
      'Name': 'Contoso',
      'Products': [
        {
          'Name': 'Elbow Grease',
          'Price': 99.95
        },
        {
          'Name': 'Headlight Fluid',
          'Price': 4
        }
      ]
    }
  ]
}");

string name = (string)o.SelectToken("Manufacturers[0].Name");

Console.WriteLine(name);
// Acme Co

decimal productPrice = (decimal)o.SelectToken("Manufacturers[0].Products[0].Price");

Console.WriteLine(productPrice);
// 50

string productName = (string)o.SelectToken("Manufacturers[1].Products[0].Name");

Console.WriteLine(productName);
// Elbow Grease

使用 JSON 路径和转义属性查询 JSON

JObject o = JObject.Parse(@"{
  'Space Invaders': 'Taito',
  'Doom ]|[': 'id',
  ""Yar's Revenge"": 'Atari',
  'Government ""Intelligence""': 'Make-Believe'
}");

string spaceInvaders = (string)o.SelectToken("['Space Invaders']");
// Taito

string doom3 = (string)o.SelectToken("['Doom ]|[']");
// id

string yarsRevenge = (string)o.SelectToken("['Yar\\'s Revenge']");
// Atari

string governmentIntelligence = (string)o.SelectToken("['Government \"Intelligence\"']");
// Make-Believe

使用复杂的 JSON 路径查询 JSON

JObject o = JObject.Parse(@"{
  'Stores': [
    'Lambton Quay',
    'Willis Street'
  ],
  'Manufacturers': [
    {
      'Name': 'Acme Co',
      'Products': [
        {
          'Name': 'Anvil',
          'Price': 50
        }
      ]
    },
    {
      'Name': 'Contoso',
      'Products': [
        {
          'Name': 'Elbow Grease',
          'Price': 99.95
        },
        {
          'Name': 'Headlight Fluid',
          'Price': 4
        }
      ]
    }
  ]
}");

// manufacturer with the name 'Acme Co'
JToken acme = o.SelectToken("$.Manufacturers[?(@.Name == 'Acme Co')]");

Console.WriteLine(acme);
// { "Name": "Acme Co", Products: [{ "Name": "Anvil", "Price": 50 }] }

// name of all products priced 50 and above
IEnumerable pricyProducts = o.SelectTokens("$..Products[?(@.Price >= 50)].Name");

foreach (JToken item in pricyProducts)
{
    Console.WriteLine(item);
}
// Anvil
// Elbow Grease

使用 JSON 路径和 LINQ 查询 JSON

此示例加载 JSON，然后使用SelectToken(String) 和 LINQ 运算符的组合从中查询值。

JObject o = JObject.Parse(@"{
  'Stores': [
    'Lambton Quay',
    'Willis Street'
  ],
  'Manufacturers': [
    {
      'Name': 'Acme Co',
      'Products': [
        {
          'Name': 'Anvil',
          'Price': 50
        }
      ]
    },
    {
      'Name': 'Contoso',
      'Products': [
        {
          'Name': 'Elbow Grease',
          'Price': 99.95
        },
        {
          'Name': 'Headlight Fluid',
          'Price': 4
        }
      ]
    }
  ]
}");

string[] storeNames = o.SelectToken("Stores").Select(s => (string)s).ToArray();

Console.WriteLine(string.Join(", ", storeNames));
// Lambton Quay, Willis Street

string[] firstProductNames = o["Manufacturers"].Select(m => (string)m.SelectToken("Products[1].Name"))
    .Where(n => n != null).ToArray();

Console.WriteLine(string.Join(", ", firstProductNames));
// Headlight Fluid

decimal totalPrice = o["Manufacturers"].Sum(m => (decimal)m.SelectToken("Products[0].Price"));

Console.WriteLine(totalPrice);
// 149.95

找不到 JSON 路径时抛出错误

JArray items = JArray.Parse(@"[
  {
    'Name': 'John Doe',
  },
  {
    'Name': 'Jane Doe',
  }
]");

// A true value for errorWhenNoMatch will result in an error if the queried value is missing 
string result;
try
{
    result = (string)items.SelectToken(@"$.[3]['Name']", errorWhenNoMatch: true);
}
catch (JsonException)
{
    result = "Unable to find result in JSON.";
}

读取和写入 JSON

使用 JsonTextReader 读取 JSON

string json = @"{
   'CPU': 'Intel',
   'PSU': '500W',
   'Drives': [
     'DVD read/writer'
     /*(broken)*/,
     '500 gigabyte hard drive',
     '200 gigabyte hard drive'
   ]
}";

JsonTextReader reader = new JsonTextReader(new StringReader(json));
while (reader.Read())
{
    if (reader.Value != null)
    {
        Console.WriteLine("Token: {0}, Value: {1}", reader.TokenType, reader.Value);
    }
    else
    {
        Console.WriteLine("Token: {0}", reader.TokenType);
    }
}

// Token: StartObject
// Token: PropertyName, Value: CPU
// Token: String, Value: Intel
// Token: PropertyName, Value: PSU
// Token: String, Value: 500W
// Token: PropertyName, Value: Drives
// Token: StartArray
// Token: String, Value: DVD read/writer
// Token: Comment, Value: (broken)
// Token: String, Value: 500 gigabyte hard drive
// Token: String, Value: 200 gigabyte hard drive
// Token: EndArray
// Token: EndObject

使用 JsonTextWriter 编写 JSON

StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);

using (JsonWriter writer = new JsonTextWriter(sw))
{
    writer.Formatting = Formatting.Indented;

    writer.WriteStartObject();
    writer.WritePropertyName("CPU");
    writer.WriteValue("Intel");
    writer.WritePropertyName("PSU");
    writer.WriteValue("500W");
    writer.WritePropertyName("Drives");
    writer.WriteStartArray();
    writer.WriteValue("DVD read/writer");
    writer.WriteComment("(broken)");
    writer.WriteValue("500 gigabyte hard drive");
    writer.WriteValue("200 gigabyte hard drive");
    writer.WriteEnd();
    writer.WriteEndObject();
}

Console.WriteLine(sb.ToString());
// {
//   "CPU": "Intel",
//   "PSU": "500W",
//   "Drives": [
//     "DVD read/writer"
//     /*(broken)*/,
//     "500 gigabyte hard drive",
//     "200 gigabyte hard drive"
//   ]
// }