ElasticSearch序列 - SpringBoot整合ES：根据指定的 ids 查询

1. ElasticSearch 根据 ids 查询文档

① 索引文档，构造数据

PUT /my_index/_doc/1
{"price":10
}PUT /my_index/_doc/2
{"price":20
}PUT /my_index/_doc/3
{"price":30
}

② 查询文档 id 为 1 或者 2 的文档：

GET /my_index/_search
{"query": {"ids": {"values": [1,2]}}
}

{"took" : 1,"timed_out" : false,"_shards" : {"total" : 1,"successful" : 1,"skipped" : 0,"failed" : 0},"hits" : {"total" : {"value" : 2,"relation" : "eq"},"max_score" : 1.0,"hits" : [{"_index" : "my_index","_type" : "_doc","_id" : "1","_score" : 1.0,"_source" : {"price" : 10}},{"_index" : "my_index","_type" : "_doc","_id" : "2","_score" : 1.0,"_source" : {"price" : 20}}]}
}

我们索引文档时，文档的id为整型，为什么查询出来的文档 id为字符串类型呢？如果我们使用字符串类型的文档id查询呢？

GET /my_index/_search
{"query": {"ids": {"values": ["1","2"]}}
}

{"took" : 2,"timed_out" : false,"_shards" : {"total" : 1,"successful" : 1,"skipped" : 0,"failed" : 0},"hits" : {"total" : {"value" : 2,"relation" : "eq"},"max_score" : 1.0,"hits" : [{"_index" : "my_index","_type" : "_doc","_id" : "1","_score" : 1.0,"_source" : {"price" : 10}},{"_index" : "my_index","_type" : "_doc","_id" : "2","_score" : 1.0,"_source" : {"price" : 20}}]}
}

可以看到仍然可以查询到匹配的文档。

在Elasticsearch中，文档ID可以是任何字符串类型，包括数字、字母、符号等。即使您在索引文档时使用了整数作为ID，Elasticsearch也会将其转换为字符串类型，并将其存储在内部索引中。当您查询文档时，Elasticsearch会将文档ID作为字符串类型返回。

如果您需要将查询结果中的文档ID转换为整数类型，可以在查询结果中进行转换。例如，在使用Java API执行查询时，您可以使用以下代码将文档ID转换为整数类型：

SearchResponse response = client.prepareSearch("my_index").setQuery(QueryBuilders.matchAllQuery()).get();for (SearchHit hit : response.getHits().getHits()) {int id = Integer.parseInt(hit.getId());// do something with the integer ID
}

在上面的代码中，我们首先执行一个查询，并使用getHits方法获取查询结果。然后，我们遍历查询结果中的每个文档，并使用Integer.parseInt方法将文档ID转换为整数类型。

2. SpringBoot整合ES实现 ids 查询

GET /my_index/_search
{"query": {"ids": {"values": [1,2]}}
}

@Slf4j
@Service
public class ElasticSearchImpl {@Autowiredprivate RestHighLevelClient restHighLevelClient;public void searchUser() throws IOException {SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();// ids 查询IdsQueryBuilder idsQueryBuilder = new IdsQueryBuilder();// IdsQueryBuilder addIds(String... ids) idsQueryBuilder.addIds("1", "2");searchSourceBuilder.query(idsQueryBuilder);SearchRequest searchRequest = new SearchRequest(new String[]{"my_index"},searchSourceBuilder);SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);System.out.println(searchResponse);}
}

如果我们想根据 ids 去查询文档的话，一般会使用 terms 查询：

GET /my_index/_search
{"query": {"terms": {"_id": ["1","2"]}}
}

需要注意的是主键为_id，而不是id，如果使用id则查询结果会为空。

@Slf4j
@Service
public class ElasticSearchImpl {@Autowiredprivate RestHighLevelClient restHighLevelClient;public void searchUser() throws IOException {SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();// terms 查询List<String> ids = Arrays.asList("1","2");TermsQueryBuilder termsQueryBuilder = new TermsQueryBuilder("_id",ids);searchSourceBuilder.query(termsQueryBuilder);SearchRequest searchRequest = new SearchRequest(new String[]{"my_index"},searchSourceBuilder);SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);System.out.println(searchResponse);}
}

{"took" : 2,"timed_out" : false,"_shards" : {"total" : 1,"successful" : 1,"skipped" : 0,"failed" : 0},"hits" : {"total" : {"value" : 2,"relation" : "eq"},"max_score" : 1.0,"hits" : [{"_index" : "my_index","_type" : "_doc","_id" : "1","_score" : 1.0,"_source" : {"price" : 10}},{"_index" : "my_index","_type" : "_doc","_id" : "2","_score" : 1.0,"_source" : {"price" : 20}}]}
}