Question

我正在尝试使用Json.NET库反序列化JSON。我收到的JSON如下：

{
    "responseHeader": {
        "zkConnected": true,
        "status": 0,
        "QTime": 2
    },
    "suggest": {
        "mySuggester": {
            "Ext": {
                "numFound": 10,
                "suggestions": [
                    {
                        "term": "Extra Community",
                        "weight": 127,
                        "payload": ""
                    },
                    {
                        "term": "External Video block",
                        "weight": 40,
                        "payload": ""
                    },
                    {
                        "term": "Migrate Extra",
                        "weight": 9,
                        "payload": ""
                    }
                ]
            }
        }
    }
}

问题在于，您可以在其中看到的“ Ext” 是查询字符串中传递的参数的一部分，并且总是不同的。我只想获取分配给术语“ term”的值。

我尝试了类似的方法，但不幸的是，它不起作用：

public class AutocompleteResultsInfo
{
    public AutocompleteResultsInfo()
    {
        this.Suggest = new Suggest();
    }
    [JsonProperty("suggest")]
    public Suggest Suggest { get; set; }
}

public class Suggest
{
    [JsonProperty("mySuggester")]
    public MySuggesterElement MySuggesterElement { get; set; }
}

public struct MySuggesterElement
{
    public MySuggester MySuggester;
    public string JsonString;

    public static implicit operator MySuggesterElement(MySuggester MySuggester) =>new MySuggesterElement { MySuggester = MySuggester };
    public static implicit operator MySuggesterElement(string String) => new MySuggesterElement { JsonString = String };
}

public class MySuggester
{
    [JsonProperty("suggestions")]
    public Suggestions[] Suggestions { get; set; }
}

public class Suggestions
{
    [JsonProperty("term")]
    public string Autocopmplete { get; set; }
}

internal class SuggesterElementConverter : JsonConverter
{
    public override bool CanConvert(Type t)
    {
        return t == typeof(MySuggesterElement) || t == typeof(MySuggesterElement?);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        switch (reader.TokenType)
        {
            case JsonToken.String:
            case JsonToken.Date:
                var stringValue = serializer.Deserialize<string>(reader);
                return new MySuggesterElement { JsonString = stringValue };
            case JsonToken.StartObject:
                var objectValue = serializer.Deserialize<MySuggester>(reader);
                return new MySuggesterElement { MySuggester = objectValue };
        }
        throw new Exception("Cannot unmarshal type MySuggesterElement");
    }

    public override void WriteJson(JsonWriter writer, object untypedValue, JsonSerializer serializer)
    {
        var value = (MySuggesterElement)untypedValue;
        if (value.JsonString != null)
        {
            serializer.Serialize(writer, value.JsonString);
            return;
        }
        if (value.MySuggester != null)
        {
            serializer.Serialize(writer, value.MySuggester);
            return;
        }
        throw new Exception("Cannot marshal type CollationElements");
    }

    public static readonly SuggesterElementConverter Singleton = new SuggesterElementConverter();
}

public class AutocompleteConverter
{
    public static readonly JsonSerializerSettings Settings = new JsonSerializerSettings
    {
        MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
        DateParseHandling = DateParseHandling.None,
        Converters =
        {
            SuggesterElementConverter.Singleton
        }
    };
}

var results = JsonConvert.DeserializeObject<AutocompleteResultsInfo>(resultJson, AutocompleteConverter.Settings);

非常感谢您的帮助。

亲切的问候， Wojciech

Answer 1

您可以将“ mySuggester”解码为字典：公共课建议

public class Suggest
{
    [JsonProperty("mySuggester")]
    public Dictionary<string, MySuggester> MySuggester { get; set; }
}

然后，您将可以使用查询字符串参数访问建议：

var variablePropertyName = "Ext";

var result = JsonConvert.DeserializeObject<AutocompleteResultsInfo>(_json);

var suggestions = result.Suggest.MySuggester[variablePropertyName].Suggestions;

如果您不知道属性名称，也可以在字典中查找它：

var variablePropertyName = result.Suggest.MySuggester.Keys.First();

工作示例： https://dotnetfiddle.net/GIKwLs

Answer 2

如果您不需要反序列化整个json字符串，则可以使用JsonTextReader。示例：

private static IEnumerable<string> GetTerms(string json)
{
    using (JsonTextReader reader = new JsonTextReader(new StringReader(json)))
    {
        while (reader.Read())
        {
            if (reader.TokenType == JsonToken.PropertyName && reader.Value.Equals("term"))
            {
                string term = reader.ReadAsString();

                yield return term;
            }
        }
    }
}

使用代码：

string json = @"{
    ""responseHeader"": {
        ""zkConnected"": true,
        ""status"": 0,
        ""QTime"": 2
    },
    ""suggest"": {
        ""mySuggester"": {
            ""Ext"": {
                ""numFound"": 10,
                ""suggestions"": [
                    {
                        ""term"": ""Extra Community"",
                        ""weight"": 127,
                        ""payload"": """"
                    },
                    {
                        ""term"": ""External Video block"",
                        ""weight"": 40,
                        ""payload"": """"
                    },
                    {
                        ""term"": ""Migrate Extra"",
                        ""weight"": 9,
                        ""payload"": """"
                    }
                ]
            }
        }
    }
}";

IEnumerable<string> terms = GetTerms(json);

foreach (string term in terms)
{
    Console.WriteLine(term);
}

Answer 3

如果您只需要包含术语的对象，而无需其他任何内容，您可以通过使用JSON.Net中的JObject接口直接使用JSON值。

var parsed = JObject.Parse(jsonString);
var usingLinq = (parsed["suggest"]["mySuggester"] as JObject)
    .Descendants()
    .OfType<JObject>()
    .Where(x => x.ContainsKey("term"));

var usingJsonPath = parsed.SelectTokens("$.suggest.mySuggester.*.*[?(@.term)]")
    .Cast<JObject>();

C＃Json.Net使用不同的“键”参数反序列化Json

3 个答案: