从 JSON 带空格的字符串反序列化枚举

Question

我将在开头说明我试图避免使用 Newtonsoft.Json，因为从表面上看，System.Text.Json 已准备好迎接 .NET 6 的黄金时段。

所以我有两个来自 API 的枚举，我想使用此测试方法反序列化它们：

[Theory]
[ClassData(typeof(TestDataGenerator))]
public void CanDeserialiseEnumsWithCustomJsonStrings(Enum expected, string jsonName)
{
    jsonName.ShouldNotBeNullOrEmpty();
    ReadOnlySpan<char> json = $"{{\"TestEnum\":\"{jsonName}\"}}";

    Type constructed = typeof(TestEnumWrapper<>).MakeGenericType(expected.GetType());
        
    var res = JsonSerializer.Deserialize(json, constructed);

    constructed.GetProperty("TestEnum").GetValue(res).ShouldBe(expected);
}

private class TestEnumWrapper<T> where T: struct
{
    public T TestEnum { get; set; }
}

（是的，我知道这可以通过 JsonSerializer.Deserialize<T>() 完成，我希望能够通过此测试测试多种类型，因此我需要反射 AFAICT）。

第一个，工作正常：

[JsonConverter(typeof(JsonStringEnumConverter))]
public enum RecordType
{
        [JsonPropertyName("country")]
        Country = 1,

        [JsonPropertyName("destinationOrbit")]
        DestinationOrbit = 2,

        [JsonPropertyName("engine")]
        Engine = 3,
        //etc...

}

第二个，反序列化失败，这似乎是由于名称中的空格。

[JsonConverter(typeof(JsonStringEnumConverter))]
public enum ObjectClass
{
    [JsonPropertyName("Rocket Body")]
    RocketBody,
    [JsonPropertyName("Rocket Debris")]
    RocketDebris,
    [JsonPropertyName("Rocket Fragmentation Debris")]
    RocketFragmentationDebris,
    [JsonPropertyName("Rocket Mission Related Object")]
    RocketMissionRelatedObject,
    //etc...
}

API 由欧洲 Space 机构控制，所以不知何故，我认为我无法说服他们使反应更加合理化。

有什么解决办法吗？

有些人要求提供 JSON 我正在尝试反序列化的示例。我目前正在处理此 blob 的属性部分：

{
            "type": "object",
            "attributes": {
                "shape": null,
                "xSectMin": null,
                "satno": null,
                "depth": null,
                "objectClass": "Rocket Fragmentation Debris",
                "cosparId": null,
                "length": null,
                "height": null,
                "mass": null,
                "xSectMax": null,
                "vimpelId": 84303,
                "xSectAvg": null,
                "name": null
            },
            "relationships": {
                "states": {
                    "links": {
                        "self": "/api/objects/61345/relationships/states",
                        "related": "/api/objects/61345/states"
                    }
                },
                "initialOrbits": {
                    "links": {
                        "self": "/api/objects/61345/relationships/initial-orbits",
                        "related": "/api/objects/61345/initial-orbits"
                    }
                },
                "destinationOrbits": {
                    "links": {
                        "self": "/api/objects/61345/relationships/destination-orbits",
                        "related": "/api/objects/61345/destination-orbits"
                    }
                },
                "operators": {
                    "links": {
                        "self": "/api/objects/61345/relationships/operators",
                        "related": "/api/objects/61345/operators"
                    }
                },
                "launch": {
                    "links": {
                        "self": "/api/objects/61345/relationships/launch",
                        "related": "/api/objects/61345/launch"
                    }
                },
                "reentry": {
                    "links": {
                        "self": "/api/objects/61345/relationships/reentry",
                        "related": "/api/objects/61345/reentry"
                    }
                }
            },
            "id": "61345",
            "links": {
                "self": "/api/objects/61345"
            }
        }

Answer 1

这是 System.Text.Json

的解决方案

我使用了 Nuget 包 System.Text.Json.EnumExtensions
https://github.com/StefH/System.Text.Json.EnumExtensions

// you probably want these options somewhere global
private JsonSerializerOptions options;

private class TestEnumWrapper<T> where T : struct
{
    public T TestEnum { get; set; }
}

public enum ObjectClass
{
    [EnumMember(Value = "Rocket Body")]
    RocketBody,
    [EnumMember(Value = "Rocket Debris")]
    RocketDebris,
    [EnumMember(Value = "Rocket Fragmentation Debris")]
    RocketFragmentationDebris,
    [EnumMember(Value = "Rocket Mission Related Object")]
    RocketMissionRelatedObject,
    //etc...
}

private void CanDeserialiseEnumsWithCustomJsonStrings(Enum expected, string jsonName)
{
    var json = $"{{\"TestEnum\":\"{jsonName}\"}}";

    Type constructed = typeof(TestEnumWrapper<>).MakeGenericType(expected.GetType());

    var res = JsonSerializer.Deserialize(json, constructed, options);
}


public void Test()
{
    this.options = new JsonSerializerOptions();
    options.Converters.Add(new JsonStringEnumConverterWithAttributeSupport());

    var testSerialize = JsonSerializer.Serialize(new TestEnumWrapper<ObjectClass>() 
        { TestEnum = ObjectClass.RocketBody }, options);

    // Test Deserialize
    CanDeserialiseEnumsWithCustomJsonStrings(ObjectClass.RocketBody, "Rocket Body");
}

您只需将 new JsonStringEnumConverterWithAttributeSupport() 添加到 JsonSerializerOptions.Converters 即可。

如果要将转换器用作属性，则必须将无参数构造函数添加到 class JsonStringEnumConverterWithAttributeSupport

public JsonStringEnumConverterWithAttributeSupport() : this(namingPolicy : null, allowIntegerValues : true,
    parseEnumMemberAttribute : true, parseDisplayAttribute : false, parseDescriptionAttribute : false)
{

}

Answer 2

试试这个，我使用 Newtonsoft.Json 并且为了测试我只反序列化了属性，因为只有它们包含枚举。您不需要任何自定义代码。

var attributes= JsonConvert.DeserializeObject<Root>(json);

类


    public enum ObjectClass
    {
    [EnumMember(Value = "Rocket Body")]
    RocketBody,
    [EnumMember(Value ="Rocket Debris")]
    RocketDebris,
    [EnumMember(Value = "Rocket Fragmentation Debris")]
    RocketFragmentationDebris,
    [EnumMember(Value ="Rocket Mission Related Object")]
    RocketMissionRelatedObject
    }

    public partial class Root
    {
        [JsonProperty("attributes")]
        public Attributes Attributes { get; set; }
    }

    public partial class Attributes
    {
        [JsonProperty("shape")]
        public object Shape { get; set; }

        [JsonProperty("xSectMin")]
        public object XSectMin { get; set; }

        [JsonProperty("satno")]
        public object Satno { get; set; }

        [JsonProperty("depth")]
        public object Depth { get; set; }

        [JsonProperty("objectClass")]
        public ObjectClass ObjectClass { get; set; }

        [JsonProperty("cosparId")]
        public object CosparId { get; set; }

        [JsonProperty("length")]
        public object Length { get; set; }

        [JsonProperty("height")]
        public object Height { get; set; }

        [JsonProperty("mass")]
        public object Mass { get; set; }

        [JsonProperty("xSectMax")]
        public object XSectMax { get; set; }

        [JsonProperty("vimpelId")]
        public long VimpelId { get; set; }

        [JsonProperty("xSectAvg")]
        public object XSectAvg { get; set; }

        [JsonProperty("name")]
        public string Name { get; set; }
    }

测试

json=JsonConvert.SerializeObject(attributes); 
attributes= JsonConvert.DeserializeObject<Root>(json);

结果

{
  "attributes": {
    "shape": null,
    "xSectMin": null,
    "satno": null,
    "depth": null,
    "objectClass": 2,
    "cosparId": null,
    "length": null,
    "height": null,
    "mass": null,
    "xSectMax": null,
    "vimpelId": 84303,
    "xSectAvg": null,
    "name": null
  }
}

从 JSON 带空格的字符串反序列化枚举

Deserialise Enum From JSON String with Spaces

c#

json

enums

deserialization

system.text.json