Question

我有一个.NET应用程序，我想用它来查询Elasticsearch。我正在成功查询我的Elasticsearch索引。结果看起来像这样：

{
  "took":31,
  "timed_out":false,
  "_shards": {
    "total":91,
    "successful":91,
    "skipped":0,
    "failed":0
  },
  "hits":{
    "total":1,
    "max_score":1.0,
    "hits":[
      {
        "_index":"my-index",
        "_type":"doc",
        "_id":"TrxrZGYQRaDom5XaZp23",
        "_score":1.0,
        "_source":{
          "my_id":"65a107ed-7325-342d-adab-21fec0a97858",
          "host":"something",
          "zip":"12345"
        }
      },
    ]
  }
}

现在，可以通过我从Elasticsearch回来的Body上的StringResponse属性获得此数据。我想将实际记录反序列化（我不需要或不需要took，timed_out等属性）到名为results的C＃对象中。为了做到这一点，我有：

var results = JsonConvert.DeserializeObject<List<Result>>(response.Body);

Result类如下所示：

public class Result
{
  [JsonProperty(PropertyName = "my_id")]
  public string Id { get; set; }

  [JsonProperty(PropertyName = "host")]
  public string Host { get; set; }

  [JsonProperty(PropertyName = "zip")]
  public string PostalCode { get; set; }
}

运行此命令时，出现以下错误：

无法将当前JSON对象反序列化为类型'System.Collections.Generic.List`1 [Result]'，因为该类型需要JSON数组才能正确反序列化。

虽然该错误有意义，但我不知道如何解析hits来提取_source数据。 _source属性包含我要反序列化的数据。其他所有内容只是我不在乎的元数据。

有没有办法做到这一点？如果可以，怎么办？

Answer 1

您可以使用Json.Net的LINQ-to-JSON API来获取您感兴趣的节点，然后将其转换为结果列表：

    axios.get('https://min-api.cryptocompare.com/data/all/coinlist') 
         .then(res => { // data
            console.log(res.data) //console
            })
   .catch(function (error) { //errors
         console.log(error);
         });     
const setAuthToken = token => {
    if(token) {
        axios.defaults.headers.common['Authorization'] = token;
    } else {
        delete axios.defaults.headers.common['Authorization']
    }
};

正在运行的演示：https://dotnetfiddle.net/OkEpPA

Answer 2

好吧，您DeserializeObject<T> T与Json不匹配。您的Json以{开头，因此您的T必须是一个类（而不是IEnumerable类型）。

让我们从外面开始，继续前进：

{
  "took":31,
  "timed_out":false,
  "_shards": <object>
  "hits": <object>
}

如此：

public class SearchResult
{
  [JsonProperty("took")]
  public int Took { get; set; }
  [JsonProperty("timed_out")]
  public bool TimedOut { get; set; }
  [JsonProperty("_shards")]
  public Shards Shards { get; set; }
  [JsonProperty("hits")]
  public Hits Hits { get; set; }
}

下一个是_shards

"_shards": {
  "total":91,
  "successful":91,
  "skipped":0,
  "failed":0
},

如此

public class Shards 
{
  [JsonProperty("total")]
  public int Total { get; set; }
  // etc...
}

然后hits

{
  "total":1,
  "max_score":1.0,
  "hits": <IEnumerable because []>
}

如此

public class Hits
{
  [JsonProperty("total")]
  public int Total { get; set; }
  [JsonProperty("max_score")]
  public int MaxScore { get; set; }
  [JsonProperty("hits")]
  public List<Hit> Hits { get; set; }
}

然后Hits列表：

{
    "_index":"my-index",
    "_type":"doc",
    "_id":"TrxrZGYQRaDom5XaZp23",
    "_score":1.0,
    "_source":  <object>
},

如此

public class Hit
{
  [JsonProperty("_index")]
  public string Index { get; set; }
  // etc
}

创建了所有所需的文件后，便会反序列化：

JsonConvert.DeserializeObject<SearchResult>(json);

Answer 3

您需要先反序列化为通用JToken或JObject，如下所示：

var token = JsonConvert.DeserializeObject<JToken>(jsonString);

然后您可以导航到保存您感兴趣的数据的 _source 属性：

var hitsArray = token["hits"]["hits"] as JArray;
var result = hitsArray[0]["_source"].ToObject<Result>();

Answer 4

我使用http://json2csharp.com/将json转换为c＃类为了测试，我从http://easyonlineconverter.com/converters/dot-net-string-escape.html

的转换中得到了一个json字符串

然后我用此类创建了一个控制台应用程序：

using System.Collections.Generic;
using Newtonsoft.Json;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string json = "{  \"took\":31,  \"timed_out\":false,  \"_shards\": {    \"total\":91,    \"successful\":91,    \"skipped\":0,    \"failed\":0  },  \"hits\":{    \"total\":1,    \"max_score\":1.0,    \"hits\":[      {        \"_index\":\"my-index\",        \"_type\":\"doc\",        \"_id\":\"TrxrZGYQRaDom5XaZp23\",        \"_score\":1.0,        \"_source\":{          \"my_id\":\"65a107ed-7325-342d-adab-21fec0a97858\",          \"host\":\"something\",          \"zip\":\"12345\"        }      },    ]  }}";
            RootObject t = JsonConvert.DeserializeObject<RootObject>(json);
        }

        public class Shards
        {
            public int total { get; set; }
            public int successful { get; set; }
            public int skipped { get; set; }
            public int failed { get; set; }
        }

        public class Source
        {
            public string my_id { get; set; }
            public string host { get; set; }
            public string zip { get; set; }
        }

        public class Hit
        {
            public string _index { get; set; }
            public string _type { get; set; }
            public string _id { get; set; }
            public double _score { get; set; }
            public Source _source { get; set; }
        }

        public class Hits
        {
            public int total { get; set; }
            public double max_score { get; set; }
            public List<Hit> hits { get; set; }
        }

        public class RootObject
        {
            public int took { get; set; }
            public bool timed_out { get; set; }
            public Shards _shards { get; set; }
            public Hits hits { get; set; }
        }
    }
}

希望这会有所帮助

Answer 5

尝试以下由VS特殊粘贴功能生成的结构：

    public class Rootobject
{
    public int took { get; set; }
    public bool timed_out { get; set; }
    public _Shards _shards { get; set; }
    public Hits hits { get; set; }
}

public class _Shards
{
    public int total { get; set; }
    public int successful { get; set; }
    public int skipped { get; set; }
    public int failed { get; set; }
}

public class Hits
{
    public int total { get; set; }
    public float max_score { get; set; }
    public Hit[] hits { get; set; }
}

public class Hit
{
    public string _index { get; set; }
    public string _type { get; set; }
    public string _id { get; set; }
    public float _score { get; set; }
    public _Source _source { get; set; }
}

public class _Source
{
    public string my_id { get; set; }
    public string host { get; set; }
    public string zip { get; set; }
}

通过JSON.NET反序列化Elasticsearch结果

5 个答案: