es跨索引查询java代码

以下是使用 Elasticsearch Java API 进行跨索引查询的示例代码：

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.common.unit.TimeValue;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.builder.SearchSourceBuilder;

import java.io.IOException;

public class CrossIndexQueryExample {

    public static void main(String[] args) throws IOException {

        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http")));

        SearchRequest searchRequest = new SearchRequest("index1", "index2");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(QueryBuilders.matchQuery("field1", "value1"));
        searchSourceBuilder.size(10);
        searchSourceBuilder.timeout(TimeValue.timeValueSeconds(10));
        searchRequest.source(searchSourceBuilder);

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

        SearchHit[] searchHits = searchResponse.getHits().getHits();
        for (SearchHit hit : searchHits) {
            String sourceAsString = hit.getSourceAsString();
            System.out.println(sourceAsString);
        }

        client.close();
    }
}

这个示例查询了 `index1` 和 `index2` 两个索引中所有 `field1` 值为 `value1` 的文档，并输出它们的 JSON 字符串。可以根据实际需要修改查询条件和输出方式。