如何在java的Elasticsearch中获取文档的父id？

import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.index.VersionType;
import org.elasticsearch.search.fetch.subphase.FetchSourceContext;

public class ElasticsearchParentIdExample {
    public static void main(String[] args) {
        // 创建Elasticsearch客户端
        RestHighLevelClient client = createElasticsearchClient();

        // 设置要获取的文档的索引、类型和ID
        String index = "your_index";
        String type = "your_type";
        String id = "your_document_id";

        // 创建获取文档的请求
        GetRequest getRequest = new GetRequest(index, id);
        getRequest.fetchSourceContext(FetchSourceContext.DO_NOT_FETCH_SOURCE);
        getRequest.storedFields("_none_");
        getRequest.versionType(VersionType.EXTERNAL);

        // 设置父ID的字段名
        getRequest.routing("your_parent_id_field");

        try {
            // 执行获取文档的请求
            GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT);

            // 获取文档的父ID
            String parentId = getResponse.getField("your_parent_id_field").getValue();

            // 打印父ID
            System.out.println("Parent ID: " + parentId);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭Elasticsearch客户端
            closeElasticsearchClient(client);
        }
    }

    private static RestHighLevelClient createElasticsearchClient() {
        // 创建并返回Elasticsearch客户端
        return new RestHighLevelClient(/* your Elasticsearch client configuration */);
    }

    private static void closeElasticsearchClient(RestHighLevelClient client) {
        // 关闭Elasticsearch客户端
        try {
            if (client != null) {
                client.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}