ElasticSearch系列 - SpringBoot整合ES：多字段查询 multi_match

1. 什么是 ElasticSearch 的 multi_match 查询？

有时用户需要在多个字段中查询关键词，除了使用布尔查询封装多个match查询之外，可替代的方案是使用multi_match。可以在multi_match的query子句中组织数据匹配规则，并在fields子句中指定需要搜索的字段列表。

以下是一个示例multi-match查询的语法：

{"query": {"multi_match": {"query": "搜索文本","fields": ["字段1", "字段2", "字段3"]}}
}

在上面的查询中，我们指定了要搜索的文本和要搜索的字段列表。ElasticSearch将搜索所有指定的字段，并将它们合并为一个结果集。

2. 如何在 multi_match 查询中指定查询字段？

在 Elasticsearch 的 multi_match 查询中，可以使用 “fields” 参数来指定要查询的字段。该参数接受一个数组，其中包含要查询的字段名称。

① 构造数据：

PUT /my_index
{"mappings": {"properties": {"title":{"type": "text"},"content":{"type": "text"}}}
}PUT /my_index/_doc/1
{"title": "Jindu Fashion Couple Romantic Theme Hotel","content": "Qingdao City"
}PUT /my_index/_doc/2
{"title": "Jindu Jiayi Holiday Inn","content": "Beijing City"
}PUT /my_index/_doc/3
{"title": "Jindu Xinxin 24 hour Hotel","content": "Huaibei City"
}

② 以下查询将在 “title” 和 “content” 字段中搜索包含 “Beijing” 和 “Xinxin” 的文档：

{"query": {"multi_match": {"query": "Beijing Xinxin","fields": ["title", "content"]}}
}

如果未指定 “fields” 参数，则默认情况下将在所有字段中搜索。

{"took" : 0,"timed_out" : false,"_shards" : {"total" : 1,"successful" : 1,"skipped" : 0,"failed" : 0},"hits" : {"total" : {"value" : 2,"relation" : "eq"},"max_score" : 0.9808292,"hits" : [{"_index" : "my_index","_type" : "_doc","_id" : "2","_score" : 0.9808292,"_source" : {"title" : "Jindu Jiayi Holiday Inn","content" : "Beijing City"}},{"_index" : "my_index","_type" : "_doc","_id" : "3","_score" : 0.9808292,"_source" : {"title" : "Jindu Xinxin 24 hour Hotel","content" : "Huaibei City"}}]}
}

3. 如何在 multi_match 查询中指定查询权重？

在 Elasticsearch 的 multi_match 查询中，可以使用 “fields” 参数来指定要搜索的字段，并使用 “^” 符号来指定每个字段的权重。

例如：“title” 的权重为 5，“content” 的权重为 2。

GET /my_index/_search
{"query": {"multi_match": {"query": "Beijing Xinxin","fields": ["title^5","content^2"]}}
}

{"took" : 1,"timed_out" : false,"_shards" : {"total" : 1,"successful" : 1,"skipped" : 0,"failed" : 0},"hits" : {"total" : {"value" : 2,"relation" : "eq"},"max_score" : 4.904146,"hits" : [{"_index" : "my_index","_type" : "_doc","_id" : "3","_score" : 4.904146,"_source" : {"title" : "Jindu Xinxin 24 hour Hotel","content" : "Huaibei City"}},{"_index" : "my_index","_type" : "_doc","_id" : "2","_score" : 1.9616584,"_source" : {"title" : "Jindu Jiayi Holiday Inn","content" : "Beijing City"}}]}
}

4. SpringBoot整合ES实现 multi_match 查询

@Slf4j
@Service
public class ElasticSearchImpl {@Autowiredprivate RestHighLevelClient restHighLevelClient;public void searchUser() throws IOException {SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();MultiMatchQueryBuilder multiMatchQueryBuilder = QueryBuilders.multiMatchQuery("Beijing Xinxin", "title", "content");searchSourceBuilder.query(multiMatchQueryBuilder);SearchRequest searchRequest = new SearchRequest(new String[]{"hotel"},searchSourceBuilder);SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);System.out.println(searchResponse);}
}

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