SpringBoot如何整合ES解析搜索返回字段问题寻技术

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1. 数据构造

索引2个文档到 hotel 索引中：

PUT /hotel/_doc/1
{
  "title": "文雅酒店",
  "city": "青岛",
  "price": 556,
  "create_time": "20200418120000",
  "amenities": "浴池,普通停车场/充电停车场",
  "full_room": false,
  "location": {
    "lat": 36.083078,
    "lon": 120.37566
  },
  "praise": 10
}

PUT /hotel/_doc/2
{
  "title": "金都嘉怡假日酒店",
  "city": "北京",
  "price": 337,
  "create_time": "20210315200000",
  "amenities": "wifi,充电停车场/可升降停车场",
  "full_room": false,
  "location": {
    "lat": 39.915153,
    "lon": 116.403
  },
  "praise": 60
}

PUT /hotel/_doc/1
{
  "title": "文雅酒店",
  "city": "青岛",
  "price": 556,
  "create_time": "20200418120000",
  "amenities": "浴池,普通停车场/充电停车场",
  "full_room": false,
  "location": {
    "lat": 36.083078,
    "lon": 120.37566
  },
  "praise": 10
}

PUT /hotel/_doc/2
{
  "title": "金都嘉怡假日酒店",
  "city": "北京",
  "price": 337,
  "create_time": "20210315200000",
  "amenities": "wifi,充电停车场/可升降停车场",
  "full_room": false,
  "location": {
    "lat": 39.915153,
    "lon": 116.403
  },
  "praise": 60
}

2. ElasticSearch 查询集群中所有索引中的所有文档

 GET /hotel/_search

{
  "took" : 499,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "hotel",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "title" : "金都嘉怡假日酒店",
          "city" : "北京",
          "price" : 337,
          "create_time" : "20210315200000",
          "amenities" : "wifi,充电停车场/可升降停车场",
          "full_room" : false,
          "location" : {
            "lat" : 39.915153,
            "lon" : 116.403
          },
          "praise" : 60
        }
      },
      {
        "_index" : "hotel",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "title" : "文雅酒店",
          "city" : "青岛",
          "price" : 556,
          "create_time" : "20200418120000",
          "amenities" : "浴池,普通停车场/充电停车场",
          "full_room" : false,
          "location" : {
            "lat" : 36.083078,
            "lon" : 120.37566
          },
          "praise" : 10
        }
      }
    ]
  }
}

3. ElasticSearch 搜索结果字段解析

1. took 搜索请求耗费了多少毫秒

took

值告诉我们执行整个搜索请求耗费了多少毫秒。

2. shards 查询中参与分片的总数

_shards

部分告诉我们在查询中参与分片的总数，以及这些分片成功了多少个失败了多少个。正常情况下我们不希望分片失败，但是分片失败是可能发生的。如果我们遭遇到一种灾难级别的故障，在这个故障中丢失了相同分片的原始数据和副本，那么对这个分片将没有可用副本来对搜索请求作出响应。假若这样，Elasticsearch 将报告这个分片是失败的，但是会继续返回剩余分片的结果。

3. timed_out 查询是否超时

timed_out

值告诉我们查询是否超时。默认情况下，搜索请求不会超时。

4. hits 表示搜索结果

返回结果中最重要的部分是

hits

，它包含

total

字段来表示匹配到的文档总数，并且一个

hits

数组包含所查询结果的前十个文档。在解析搜索结果时，我们通常需要关注以下几个字段：

hits.total.value：匹配的文档总数。
hits.max_score：与查询所匹配文档的_score的最大值。
hits.hits：匹配的文档列表。
hits.hits._source：匹配的文档的原始数据。
hits.hits._score：匹配的文档的分数。它衡量了文档与查询的匹配程度,默认情况下，首先返回最相关的文档结果，就是说，返回的文档是按照score 降序排列的。
hits.hits.highlight：匹配的文档的高亮显示信息。

4. SpringBoot 整合ElasticSearch获取搜索结果

@Slf4j
@Service
public class ElasticSearchImpl {

    @Autowired
    private RestHighLevelClient restHighLevelClient;

    public void searchUser() throws IOException {
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        SearchRequest searchRequest = new SearchRequest(new String[]{"hotel"},searchSourceBuilder);
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        TimeValue took = searchResponse.getTook();
        System.out.println("took = " + took);

        // 搜索结果
        SearchHits searchHits = searchResponse.getHits();

        // hits.total.value:匹配的文档总数
        TotalHits totalHits = searchHits.getTotalHits();
        long value = totalHits.value;
        System.out.println("value = " + value);

        // hits.max_score:与查询所匹配文档的_score的最大值
        float maxScore = searchHits.getMaxScore();
        System.out.println("maxScore = " + maxScore);

        // hits.hits:匹配的文档列表
        SearchHit[] hits = searchHits.getHits();
        for (SearchHit hit : hits) {
            // hits.hits._source：匹配的文档的原始数据
            String sourceAsString = hit.getSourceAsString();
            System.out.println("sourceAsString = " + sourceAsString);

            //  hits.hits._id：匹配的文档的id
            String id = hit.getId();
            System.out.println("id = " + id);

            Map<String, DocumentField> fields = hit.getFields();
            System.out.println("fields = " + fields);

            String index = hit.getIndex();
            System.out.println("index = " + index);

            float score = hit.getScore();
            System.out.println("score = " + score);
        }
        System.out.println(searchResponse);

    }
}

@Slf4j
@Service
public class ElasticSearchImpl {

    @Autowired
    private RestHighLevelClient restHighLevelClient;

    public void searchUser() throws IOException {
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        SearchRequest searchRequest = new SearchRequest(new String[]{"hotel"},searchSourceBuilder);
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        TimeValue took = searchResponse.getTook();
        System.out.println("took = " + took);

        // 搜索结果
        SearchHits searchHits = searchResponse.getHits();

        // hits.total.value:匹配的文档总数
        TotalHits totalHits = searchHits.getTotalHits();
        long value = totalHits.value;
        System.out.println("value = " + value);

        // hits.max_score:与查询所匹配文档的_score的最大值
        float maxScore = searchHits.getMaxScore();
        System.out.println("maxScore = " + maxScore);

        // hits.hits:匹配的文档列表
        SearchHit[] hits = searchHits.getHits();
        for (SearchHit hit : hits) {
            // hits.hits._source：匹配的文档的原始数据
            String sourceAsString = hit.getSourceAsString();
            System.out.println("sourceAsString = " + sourceAsString);

            //  hits.hits._id：匹配的文档的id
            String id = hit.getId();
            System.out.println("id = " + id);

            Map<String, DocumentField> fields = hit.getFields();
            System.out.println("fields = " + fields);

            String index = hit.getIndex();
            System.out.println("index = " + index);

            float score = hit.getScore();
            System.out.println("score = " + score);
        }
        System.out.println(searchResponse);

    }
}

took=2ms
value = 2
maxScore = 1.0

sourceAsString = {"title":"金都嘉怡假日酒店","city":"北京","price":337,"create_time":"20210315200000","amenities":"wifi,充电停车场/可升降停车场","full_room":false,"location":{"lat":39.915153,"lon":116.403},"praise":60}
id = 2
fields = {}
index = hotel
score = 1.0

sourceAsString = {"title":"文雅酒店","city":"青岛","price":556,"create_time":"20200418120000","amenities":"浴池,普通停车场/充电停车场","full_room":false,"location":{"lat":36.083078,"lon":120.37566},"praise":10}
id = 1
fields = {}
index = hotel
score = 1.0

{
    "took": 2,
    "timed_out": false,
    "_shards": {
        "total": 5,
        "successful": 5,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": {
            "value": 2,
            "relation": "eq"
        },
        "max_score": 1.0,
        "hits": [
            {
                "_index": "hotel",
                "_type": "_doc",
                "_id": "2",
                "_score": 1.0,
                "_source": {
                    "title": "金都嘉怡假日酒店",
                    "city": "北京",
                    "price": 337,
                    "create_time": "20210315200000",
                    "amenities": "wifi,充电停车场/可升降停车场",
                    "full_room": false,
                    "location": {
                        "lat": 39.915153,
                        "lon": 116.403
                    },
                    "praise": 60
                }
            },
            {
                "_index": "hotel",
                "_type": "_doc",
                "_id": "1",
                "_score": 1.0,
                "_source": {
                    "title": "文雅酒店",
                    "city": "青岛",
                    "price": 556,
                    "create_time": "20200418120000",
                    "amenities": "浴池,普通停车场/充电停车场",
                    "full_room": false,
                    "location": {
                        "lat": 36.083078,
                        "lon": 120.37566
                    },
                    "praise": 10
                }
            }
        ]
    }
}

5 .ElasticSearch 搜索结果的面试题

1. ElasticSearch 搜索结果中的 _score 字段是什么意思？

答：_score 字段表示匹配文档的相关度得分，分数越高表示匹配度越高。

2. ElasticSearch 搜索结果中的 highlight 字段是什么意思？

答：highlight 字段表示匹配文档中被高亮显示的字段及其高亮显示的内容。

3. 如何获取 ElasticSearch 搜索结果中的总文档数？

答：可以通过 hits.total.value 字段获取匹配的文档总数。

4. 如何获取 ElasticSearch 搜索结果中的匹配文档列表？

答：可以通过 hits.hits 字段获取匹配的文档列表。

5. 如何获取 ElasticSearch 搜索结果中匹配文档的原始数据？

答：可以通过 hits.hits._source 字段获取匹配文档的原始数据。

6. 如何获取 ElasticSearch 搜索结果中匹配文档的高亮显示信息？