C# Newtonsoft.Json JsonSerializerSettings配置

本文轉載自查看原文 2019-11-27 11:02 431 C#

JsonSerializerSettings常用配置整理

1.忽略某些屬性

MemberSerialization.OptIn

默認情況下,所有的成員不會被序列化,類中的成員只有標有特性JsonProperty的才會被序列化,當類的成員很多,但客戶端僅僅需要一部分數據時,很有用

 1     [JsonObject(MemberSerialization.OptIn)]
 2     public class TestClass
 3     {
 4         public int A { get; set; }
 5         public long B { get; set; }
 6         public string C { get; set; }
 7         [JsonProperty]
 8         public DateTime D { get; set; }
 9         public TestEnum E { get; set; }
10         [JsonIgnore]
11         public TestClass F { get; set; }
12         public List<TestClass> G { get; set; }
13         public bool H { get; set; }
14     }
15     public enum TestEnum
16     {
17         TestEnum0 = 0,
18         TestEnum1 = 1,
19         TestEnum2 = 2,
20         TestEnum3 = 3,
21     }
22     [JsonObject(MemberSerialization.OptIn)]
23     public class Person
24     {
25         [JsonIgnore]
26         public string Name { get; set; }
27         [JsonProperty]
28         public int Age { get; set; }
29         public DateTime BirthDay { get; set; }
30     }

View Code

 1                 Console.WriteLine(JsonConvert.SerializeObject(new Person { Name = "test", Age = 18, BirthDay = new DateTime(2011, 1, 1) }));
 2                 TestClass testClass = new TestClass
 3                 {
 4                     A = 1,
 5                     B = 2,
 6                     C = "C",
 7                     D = DateTime.Now,
 8                     E = TestEnum.TestEnum1,
 9                     F = new TestClass
10                     {
11                         A = 11,
12                         B = 22,
13                         C = "Cc",
14                         D = DateTime.Now,
15                         E = TestEnum.TestEnum2,
16                         F = new TestClass()
17                     },
18                     G = new List<TestClass>
19                 {
20                     new TestClass
21                     {
22                         A=111,
23                         B=222,
24                         C="CCC",
25                         E=TestEnum.TestEnum1,
26                         F=new TestClass()
27                     }
28                 }
29                 };
30                 Console.WriteLine(JsonConvert.SerializeObject(testClass));

View Code

輸出結果：

{"Age":18}
{"D":"2019-11-26T10:37:33.7655514+08:00"}

MemberSerialization.OptOut

默認類中所有公有成員會被序列化,如果不想被序列化,可以用特性JsonIgnore

將上面的代碼OptIn改為OptOut輸出結果：

{"Age":18,"BirthDay":"2011-01-01T00:00:00"}
{"A":1,"B":2,"C":"C","D":"2019-11-26T15:49:37.9507028+08:00","E":1,"G":[{"A":111,"B":222,"C":"CCC","D":"0001-01-01T00:00:00","E":1,"G":null,"H":false}],"H":false}

2.默認值的處理

DefaultValueHandling.Ignore 序列化和反序列化時,忽略默認值

 1                 TestClass testClass = new TestClass
 2                 {
 3                     A = 1,
 4                     B = 2,
 5                     C = "C",
 6                     D = DateTime.Now,
 7                     E = TestEnum.TestEnum1,
 8                     F = new TestClass
 9                     {
10                         A = 11,
11                         B = 22,
12                         C = "Cc",
13                         D = DateTime.Now,
14                         E = TestEnum.TestEnum2,
15                         F = new TestClass()
16                     },
17                     G = new List<TestClass>
18                      {
19                          new TestClass
20                          {
21                              A=111,
22                              B=222,
23                              C="CCC",
24                              E=TestEnum.TestEnum1,
25                              F=new TestClass()
26                          }
27                      }
28                 };
29                 JsonSerializerSettings settings = new JsonSerializerSettings();
30                 settings.DefaultValueHandling = DefaultValueHandling.Ignore;
31                 Console.WriteLine(JsonConvert.SerializeObject(testClass,settings));

View Code

輸出結果：

{"A":1,"B":2,"C":"C","D":"2019-11-26T15:56:21.7204132+08:00","E":1,"G":[{"A":111,"B":222,"C":"CCC","E":1}]}

DefaultValueHandling.Include 序列化和反序列化時,包含默認值

將JsonSerializerSettings.DefaultValueHandling屬性設為DefaultValueHandling.Include輸出結果：

{"A":1,"B":2,"C":"C","D":"2019-11-26T16:21:48.5429746+08:00","E":1,"G":[{"A":111,"B":222,"C":"CCC","D":"0001-01-01T00:00:00","E":1,"G":null,"H":false}],"H":false}

DefaultValueHandling.Populate 在反序列化時，具有默認值但沒有JSON的成員將被設置為其默認值。

DefaultValueHandling.IgnoreAndPopulate 在序列化對象時忽略成員值與成員默認值相同的成員，在反序列化時將成員設置為其默認值

不指定的情況下，序列化時默認包含-DefaultValueHandling.Include

3.空值的處理

設置JsonSerializerSettings.NullValueHandling屬性

對序列化過程中所有屬性生效的，想單獨對某一個屬性生效可以使用JsonProperty

值為NullValueHandling.Ignore時，輸出結果為：

{"A":1,"B":2,"C":"C","D":"2019-11-26T16:34:21.3205145+08:00","E":1,"G":[{"A":111,"B":222,"C":"CCC","D":"0001-01-01T00:00:00","E":1,"H":false}],"H":false}

值為NullValueHandling.Include時，輸出結果為：

{"A":1,"B":2,"C":"C","D":"2019-11-26T16:34:21.3205145+08:00","E":1,"G":[{"A":111,"B":222,"C":"CCC","D":"0001-01-01T00:00:00","E":1,"G":null,"H":false}],"H":false}

4.支持非公共成員

序列化時默認都是處理公共成員，如果需要處理非公共成員，就要在該成員上加特性JsonProperty

5.日期處理（DateFormatHandling）

對於Dateime類型日期的格式化，系統自帶的會格式化成iso日期標准{"BirthDay":"2011-01-01T00:00:00"}

解決方案1：添加特性，指定轉換格式

1     public class LongDateTimeConvert: Newtonsoft.Json.Converters.IsoDateTimeConverter
2     {
3         public LongDateTimeConvert() : base()
4         {
5             base.DateTimeFormat = "yyyy-MM-dd";
6         }
7     }
8         //[JsonConverter(typeof(LongDateTimeConvert))]
9         public DateTime BirthDay { get; set; }

View Code

輸出結果：{"BirthDay":"2011-01-01"}

解決方案2：指定JsonSerializerSettings.DateFormatString的值

1                 JsonSerializerSettings settings = new JsonSerializerSettings();
2                 settings.DateFormatString = "yyyy-MM-dd HH:mm:ss";
3                 var str = JsonConvert.SerializeObject(new Person { Name = "test", Age = 18, BirthDay = new DateTime(2011, 1, 1) }, settings);
4                 Console.WriteLine(str);

View Code

輸出結果：{"BirthDay":"2011-01-01 00:00:00"}

同時指定時以特性（即方案1）為准

6.自定義序列化的字段名稱

實體中定義的屬性名可能不是自己想要的名稱，但是又不能更改實體定義，這個時候可以自定義序列化字段名稱

[JsonProperty(PropertyName = "age")]
public int Age { get; set; }

輸出結果：{"age":18}

7.動態決定屬性是否序列化

指定JsonSerializerSettings.ContractResolver的實例，繼承DefaultContractResolver類，重寫方法

 1     public class JsonContractResolver : DefaultContractResolver
 2     {
 3         protected IEnumerable<string> _excludedProperties;
 4         public JsonContractResolver(IEnumerable<string> excludedProperties)
 5         {
 6             this._excludedProperties = excludedProperties;
 7         }
 8         protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
 9         {
10             return base.CreateProperties(type, memberSerialization).Where(a=>!this._excludedProperties.Contains(a.PropertyName)).ToList();
11         }
12     }
13                 JsonSerializerSettings settings = new JsonSerializerSettings();
14                 settings.ContractResolver =new JsonContractResolver(new[] { "Sign" });
15                 settings.DateFormatHandling = DateFormatHandling.MicrosoftDateFormat;
16                 settings.DateFormatString = "yyyy-MM-dd HH:mm:ss";
17                 var str = JsonConvert.SerializeObject(new Person { Name = "test", Age = 18, BirthDay = new DateTime(2011, 1, 1) }, settings);
18                 Console.WriteLine(str);

View Code

過濾屬性名為Sign的字段，輸出結果：{"age":18,"BirthDay":"2011-01-01T00:00:00"}

8.枚舉值的自定義格式化問題

默認枚舉輸出的是枚舉的值 {"E":1}

在屬性上加上JsonConverter(typeof(StringEnumConverter))表示將枚舉值轉換成對應的字符串,StringEnumConverter是Newtonsoft.Json內置的轉換類型

輸出結果：{"E":"TestEnum1"}

9.自定義類型轉換

需要擴展類JsonConverter類

10.全局序列化設置

1                 JsonSerializerSettings settings = new JsonSerializerSettings();
2                 settings.ContractResolver =new JsonContractResolver(new[] { "Sign" });
3                 settings.DateFormatHandling = DateFormatHandling.MicrosoftDateFormat;
4                 settings.DateFormatString = "yyyy-MM-dd HH:mm:ss";
5                 JsonConvert.DefaultSettings = () => settings;

View Code

指定JsonConvert.DefaultSettings

11.指定序列化時Key的處理方式：駝峰樣式，默認樣式（ContractResolver）

JsonSerializerSettings settings = new JsonSerializerSettings();
settings.ContractResolver = new CamelCasePropertyNamesContractResolver();

var str = JsonConvert.SerializeObject(new Person { Name = "test", Age = 18, BirthDay = new DateTime(2011, 1, 1) },Formatting.Indented);

Formatting.Indented 格式化json字符串數據,鋸齒狀的

輸出結果：

{
"sign": false,
"age": 18,
"birthDay": "2011-01-01T00:00:00"
}

12.序列化循環引用及處理層數

對於關聯表的對象或列表都不會序列化出來

//設置循環引用，及引用類型序列化的層數。
//注：目前在 EF core中目前不支持延遲加載，無所謂循環引用了
JsonSerializerSettings settings = new JsonSerializerSettings();
settings.Formatting = Formatting.Indented;
settings.MaxDepth = 10; //設置序列化的最大層數
settings.ReferenceLoopHandling = ReferenceLoopHandling.Serialize;//指定如何處理循環引用，None--不序列化，Error-拋出異常，Serialize--仍要序列化

本文參考文檔：

https://blog.csdn.net/u011127019/article/details/72801033

Newtonsoft.Json 官方文檔：https://www.newtonsoft.com/json/help/html/T_Newtonsoft_Json_JsonSerializerSettings.htm

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