ElasticSearchRestTemplate 聚合分页查询代码示例

当使用 ElasticSearch 的 RestTemplate 进行聚合分页查询时，你可以按照以下示例代码进行操作：

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.unit.TimeValue;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.sort.SortBuilders;
import org.elasticsearch.search.sort.SortOrder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
import org.springframework.data.elasticsearch.core.SearchHit;
import org.springframework.data.elasticsearch.core.SearchHits;
import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class AggregationPaginationExample {

    @Autowired
    private RestHighLevelClient restHighLevelClient;

    @Autowired
    private ElasticsearchRestTemplate elasticsearchRestTemplate;

    public void searchWithAggregationAndPagination() throws IOException {
        SearchRequest searchRequest = new SearchRequest("your_index_name");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

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

        // 设置排序规则
        searchSourceBuilder.sort(SortBuilders.fieldSort("your_field_name").order(SortOrder.DESC));

        // 设置分页参数
        searchSourceBuilder.from(0);
        searchSourceBuilder.size(10);

        // 设置聚合条件
        searchSourceBuilder.aggregation(
                AggregationBuilders.terms("your_aggregation_name").field("your_field_name")
        );

        searchRequest.source(searchSourceBuilder);

        // 执行查询
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        
        // 解析结果
        SearchHits<YourEntityClass> searchHits = elasticsearchRestTemplate.search(searchRequest, YourEntityClass.class, IndexCoordinates.of("your_index_name"));
        for (SearchHit<YourEntityClass> searchHit : searchHits) {
            YourEntityClass entity = searchHit.getContent();
            // 处理每个匹配的实体
        }

        // 解析聚合结果
        Terms aggregation = searchResponse.getAggregations().get("your_aggregation_name");
        for (Terms.Bucket bucket : aggregation.getBuckets()) {
            String keyAsString = bucket.getKeyAsString();
            long docCount = bucket.getDocCount();
            // 处理每个聚合结果
        }
    }
}

在上述示例代码中，你需要替换以下部分：

- `your_index_name`：替换为你的索引名称。
- `your_field_name`：替换为你的字段名称。
- `your_aggregation_name`：替换为你的聚合名称。
- `YourEntityClass`：替换为你的实体类名称。

请确保已经正确配置了 ElasticSearch 的连接信息，并且已经导入了相应的依赖。另外，该示例使用了 Spring Data Elasticsearch 的 RestTemplate 进行操作。