仅返回弹性搜索原生查询Java api中的特定字段

Elasticsearch 原生查询 Java API 中返回特定字段

在 Elasticsearch 的 Java API 中，要仅返回查询结果中的特定字段，可以使用 FetchSourceContext 和 SourceFilter 来实现。以下是几种实现方式：

方法一：使用 FetchSourceContext

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.FetchSourceContext;

// 创建搜索请求
SearchRequest searchRequest = new SearchRequest("your_index_name");
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

// 设置查询条件
sourceBuilder.query(QueryBuilders.matchAllQuery());

// 设置返回的字段
String[] includeFields = new String[] {"field1", "field2"};
String[] excludeFields = new String[] {};
FetchSourceContext fetchSourceContext = 
    new FetchSourceContext(true, includeFields, excludeFields);

sourceBuilder.fetchSource(fetchSourceContext);

searchRequest.source(sourceBuilder);

// 执行查询
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);

方法二：使用 SourceFilter

import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
import org.elasticsearch.search.fetch.subphase.FieldAndFormat;

// 创建搜索请求
SearchRequest searchRequest = new SearchRequest("your_index_name");
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

// 设置查询条件
sourceBuilder.query(QueryBuilders.matchAllQuery());

// 设置返回的字段
sourceBuilder.fetchSource(
    new FetchSourceContext(true, new String[]{"field1", "field2"}, new String[]{})
);

searchRequest.source(sourceBuilder);

// 执行查询
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);

方法三：使用 includes/excludes

SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchAllQuery());

// 只包含field1和field2，排除其他字段
sourceBuilder.fetchSource(new String[]{"field1", "field2"}, null);

SearchRequest searchRequest = new SearchRequest("your_index_name");
searchRequest.source(sourceBuilder);

SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);

方法四：使用字段过滤（适用于高版本ES）

SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchAllQuery());

// 添加需要返回的字段
sourceBuilder.fetchField("field1");
sourceBuilder.fetchField("field2");

SearchRequest searchRequest = new SearchRequest("your_index_name");
searchRequest.source(sourceBuilder);

SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);