Question

我有一个.Net对象，我已经将其序列化为Xml并使用Xml属性进行修饰。我现在想将同一个对象序列化为Json，最好使用Newtonsoft Json.Net库。

我想直接从内存中的.Net对象转到Json字符串（不先串行化为Xml）。我不希望在类中添加任何Json属性，而是希望Json序列化程序使用现有的Xml属性。

public class world{
  [XmlIgnore]
  public int ignoreMe{ get; }

  [XmlElement("foo")]
  public int bar{ get; }

  [XmlElement("marco")]
  public int polo{ get; }
}

变为

{
  "foo":0,
  "marco":0
}

Answer 1

使用[JsonProperty(PropertyName="foo")]属性并设置PropertyName。

Answer 2

原来这不是Newtonsoft Json.Net库的现有功能。我已经编写了一个补丁并将其上传到Json.Net issue tracker（已存档的链接here）：

这允许以下内容：

XmlIgnore就像JsonIgnore一样。
XmlElementAttribute.ElementName将改变Json属性名称。
XmlType.AnonymousType会禁止将对象打印到Json（XmlContractResolver.SuppressAnonymousType属性会改变这种行为）这有点hacky，因为我必须学习Json.Net的内部因为我一直在去

Answer 3

您可以创建一个自定义合约解析程序，它允许您对属性进行调整，并将它们设置为忽略XmlIgnoreAttribute的设置位置。

public class CustomContractResolver : DefaultContractResolver
{
    private readonly JsonMediaTypeFormatter formatter;

    public CustomContractResolver(JsonMediaTypeFormatter formatter)
    {
        this.formatter = formatter;
    }

    public JsonMediaTypeFormatter Formatter
    {
        [DebuggerStepThrough]
        get { return this.formatter; }
    }

    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        JsonProperty property = base.CreateProperty(member, memberSerialization);
        this.ConfigureProperty(member, property);
        return property;
    }

    private void ConfigureProperty(MemberInfo member, JsonProperty property)
    {
        if (Attribute.IsDefined(member, typeof(XmlIgnoreAttribute), true))
        {
            property.Ignored = true;
        }            
    }
}

您可以使用在序列化对象时通过设置JsonSerializerSettings的ContractResolver属性来应用此自定义解析器

https://www.newtonsoft.com/json/help/html/ContractResolver.htm

string json =
    JsonConvert.SerializeObject(
        product, // this is your object that has xml attributes on it that you want ignored
        Formatting.Indented,
        new JsonSerializerSettings { ContractResolver = new CustomResolver() }
        );

如果您正在使用WebApi，则可以全局设置以应用于所有合同。

var config = GlobalConfiguration.Configuration;
var jsonSettings = config.Formatters.JsonFormatter.SerializerSettings;
jsonSettings.ContractResolver = new CustomContractResolver();

Answer 4

下面的类可用于将对象树的部分序列化（和反序列化）为XML，然后再序列化为JSON。

<强>用法

[JsonObject]
public class ClassToSerializeWithJson
{
    [JsonProperty]
    public TypeThatIsJsonSerializable PropertySerializedWithJsonSerializer {get; set; }

    [JsonProperty]
    [JsonConverter(typeof(JsonXmlConverter<TypeThatIsXmlSerializable>))]
    public TypeThatIsXmlSerializable PropertySerializedWithCustomSerializer {get; set; }
}

JsonXmlConverter类

public class JsonXmlConverter<TType> : JsonConverter where TType : class
{
    private static readonly XmlSerializer xmlSerializer = new XmlSerializer(typeof(TType));

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var xml = ToXml(value as TType);
        using (var stream = new StringReader(xml))
        {
            var xDoc = XDocument.Load(stream);
            var json = JsonConvert.SerializeXNode(xDoc);
            writer.WriteRawValue(json);
        }
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        if (reader.TokenType == JsonToken.Null) 
        { 
            // consume the 'null' token to set the reader in the correct state
            JToken.Load(reader); 
            return null; 
        }
        var jObj = JObject.Load(reader);
        var json = jObj.ToString();
        var xDoc = JsonConvert.DeserializeXNode(json);
        var xml = xDoc.ToString();
        return FromXml(xml);
    }

    public override bool CanRead => true;

    public override bool CanConvert(Type objectType) => objectType == typeof(TType);

    private static TType FromXml(string xmlString)
    {
        using (StringReader reader = new StringReader(xmlString))
            return (TType)xmlSerializer.Deserialize(reader);
    }

    private static string ToXml(TType obj)
    {
        using (StringWriter writer = new StringWriter())
        using (XmlWriter xmlWriter = XmlWriter.Create(writer))
        {
            XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
            ns.Add(String.Empty, String.Empty);

            xmlSerializer.Serialize(xmlWriter, obj, ns);
            return writer.ToString();
        }
    }
}

将.Net对象序列化为json，使用xml属性进行控制

4 个答案: