java通过api怎么实现这个查询

以下是Java API实现去重取第一条数据的示例代码：

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.index.query.QueryBuilders;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.aggregations.metrics.TopHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;

import java.io.IOException;

public class DeduplicationExample {

    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(/* your client configuration */);

        SearchRequest request = new SearchRequest("your_index_name");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        // 添加需要去重的字段和排序字段
        sourceBuilder.aggregation(
            AggregationBuilders.terms("dedup")
                .field("field")
                .size(10000)
                .subAggregation(
                    AggregationBuilders.topHits("dedup_docs")
                        .size(1)
                        .sort("sort_field", SortOrder.DESC)
                )
        );

        // 添加需要的查询条件
        sourceBuilder.query(QueryBuilders.matchAllQuery());

        request.source(sourceBuilder);

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

        // 解析聚合结果
        Terms dedupAgg = response.getAggregations().get("dedup");
        for (Terms.Bucket bucket : dedupAgg.getBuckets()) {
            TopHits dedupDocsAgg = bucket.getAggregations().get("dedup_docs");
            // 取第一条去重后的数据
            System.out.println(dedupDocsAgg.getHits().getAt(0).getSourceAsString());
        }

        client.close();
    }
}

这个示例代码使用了Elasticsearch Java High Level REST Client来进行API调用，具体的client配置和依赖项需要根据实际情况进行设置。在代码中，我们首先构建了一个SearchRequest，然后使用SearchSourceBuilder来设置需要的查询条件和聚合信息。最后使用RestHighLevelClient执行查询，并解析聚合结果。