OpenSearch:Exemple de code pour implémenter les requêtes de défilement (scroll)

package com.aliyun.opensearch;

import com.aliyun.opensearch.OpenSearchClient;
import com.aliyun.opensearch.SearcherClient;
import com.aliyun.opensearch.sdk.dependencies.com.google.common.collect.Lists;
import com.aliyun.opensearch.sdk.dependencies.org.json.JSONObject;
import com.aliyun.opensearch.sdk.generated.OpenSearch;
import com.aliyun.opensearch.sdk.generated.commons.OpenSearchClientException;
import com.aliyun.opensearch.sdk.generated.commons.OpenSearchException;
import com.aliyun.opensearch.sdk.generated.search.*;
import com.aliyun.opensearch.sdk.generated.search.general.SearchResult;
import com.aliyun.opensearch.search.SearchParamsBuilder;

import java.nio.charset.Charset;

public class testScroll {

    // Scroll queries do not support the aggregate, distinct, or rank clause,
    // but do support sorting by a single field.
    private static String appName = "The name of the OpenSearch application for which you want to implement scroll queries";
    private static String host = "The endpoint of the OpenSearch API in your region";

    public static void main(String[] args) {
        // Read credentials from environment variables.
        // Configure the environment variables before running this code.
        String accesskey = System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID");
        String secret = System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET");

        // Print the default encoding format.
        System.out.println(String.format("file.encoding: %s", System.getProperty("file.encoding")));
        System.out.println(String.format("defaultCharset: %s", Charset.defaultCharset().name()));

        // Create an OpenSearch object.
        OpenSearch openSearch = new OpenSearch(accesskey, secret, host);

        // Create an OpenSearchClient object.
        OpenSearchClient serviceClient = new OpenSearchClient(openSearch);

        // Create a SearcherClient object.
        SearcherClient searcherClient = new SearcherClient(serviceClient);

        // Configure the config clause: paging settings, data format, and application name.
        Config config = new Config(Lists.newArrayList(appName));

        // The start parameter has no effect on scroll queries. The offset is always 0.
        config.setStart(0);
        // Return 5 documents per batch.
        config.setHits(5);

        // Set the data format to FULLJSON. Supported formats: JSON, FULLJSON.
        config.setSearchFormat(SearchFormat.FULLJSON);

        // Specify the fields to return.
        config.setFetchFields(Lists.newArrayList("id", "name", "phone", "int_arr", "literal_arr", "float_arr", "cate_id"));
        // Note: Set rerank_size using the setReRankSize method of the Rank class.

        // Create a SearchParams object and set the search query.
        SearchParams searchParams = new SearchParams(config);

        // To query multiple index fields, specify all fields in a single setQuery call.
        // Separate setQuery calls overwrite each other.
        searchParams.setQuery("name:'opensearch'");

        // (Optional) Set a filter condition.
        // searchParams.setFilter("cate_id<=3");

        // Create a DeepPaging object to enable scroll queries.
        DeepPaging deep = new DeepPaging();
        // Specify a validity period for the scroll ID to be used by the next scroll query, in minutes.
        // Default value: 1m. In this example, the value is set to 3m.
        deep.setScrollExpire("3m");

        // Attach the DeepPaging object to the search parameters.
        searchParams.setDeepPaging(deep);

        // Create a SearchParamsBuilder for easier parameter configuration.
        SearchParamsBuilder paramsBuilder = SearchParamsBuilder.create(searchParams);

        // Run the scroll queries.
        // This example assumes 25 matching documents with 5 documents per batch,
        // so 5 batches return results and the 6th batch is empty.
        SearchResult searchResult;
        try {
            searchResult = searcherClient.execute(paramsBuilder);
            String result = searchResult.getResult();
            JSONObject obj = new JSONObject(result);

            for (int i = 1; i <= 6; i++) {
                // When you run the first scroll query, a scroll ID is returned.
                // To obtain document data, use this scroll ID to run the scroll query again.
                deep.setScrollId(new JSONObject(obj.get("result").toString()).get("scroll_id").toString());
                // Specify a validity period for the scroll ID to be used by the next scroll query, in minutes.
                // Default value: 1m. In this example, the value is set to 3m.
                // If you do not want to use the default value, you must set a validity period each time before you run a scroll query.
                deep.setScrollExpire("3m");

                searchResult = searcherClient.execute(paramsBuilder);
                result = searchResult.getResult();
                obj = new JSONObject(result);

                System.out.println("Results for Query No." + i + ": " + obj.get("result"));

                // Sleep for 1 second to avoid exceeding the queries per second (QPS) limit.
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }

        } catch (OpenSearchException e) {
            e.printStackTrace();
        } catch (OpenSearchClientException e) {
            e.printStackTrace();
        }
    }
}