Rest Client操作向量索引示例

更新时间：2024-02-27

本文基于Java High Level REST Client 7.x 和 Java Low Level REST Client 7.x 版本，为您介绍Elasticsearch Java API的用法。

准备工作

安装Java，要求JDK版本为1.8及以上。
创建Baidu Elasticsearch实例，版本7.10.2。

采用 High Level Client 进行创建索引，写入数据，refresh 以及删除索引操作，采用 Low Level Client 执行检索数据操作。

注意 High Level Client能够向上兼容，但为了保证最大程度地使用最新版客户端的特性，推荐High Level Client版本与集群版本一致。

注意 Low Level Client能够与任何版本的Elasticsearch兼容，因此客户端版本可以为任何版本，本文以7.10.2版本为例。
创建Java Maven工程，并将如下的pom依赖添加到Java工程的pom.xml文件中。

pom依赖

                XML
                
            

                <dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.10.2</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.7</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.7</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-client</artifactId>
    <version>7.10.2</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpasyncclient</artifactId>
    <version>4.1.4</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore-nio</artifactId>
    <version>4.4.13</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.6</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.12</version>
</dependency>
            

示例

以下示例采用 High Level Client 执行创建索引操作、写入数据、refresh 操作以及删除索引操作，采用 Low Level Client 执行检索数据操作，可供参考。

                Java
                
            

                import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.entity.ContentType;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
import org.apache.http.nio.entity.NStringEntity;
import org.apache.http.util.EntityUtils;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
import org.elasticsearch.action.admin.indices.refresh.RefreshRequest;
import org.elasticsearch.action.admin.indices.refresh.RefreshResponse;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.support.master.AcknowledgedResponse;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.Request;
import org.elasticsearch.client.Response;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.CreateIndexResponse;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentType;

import java.io.IOException;
import java.util.Random;

public class RestClientTest710 {

    public static void main(String[] args) {
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        //访问用户名和密码为您创建Elasticsearch实例时设置的用户名和密码。
        credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials("{访问用户名}", "{访问密码}"));
        // 通过builder创建high level rest client，配置http client的HttpClientConfigCallback。
        // ES HTTP URL 在Baidu Elasticsearch界面中可以查询
        RestClientBuilder builder = RestClient.builder(new HttpHost("{ES HTTP URL}", 8200))
                .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                    @Override
                    public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                        return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
                    }
                });

        // RestHighLevelClient实例通过REST low-level client builder进行构造。
        RestHighLevelClient client = new RestHighLevelClient(builder);

        // 通过 restClient 进行查询操作
        RestClient restClient = RestClient.builder(new HttpHost("{ES HTTP URL}", 8200))
                .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                    @Override
                    public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                        return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
                    }
                }).build();

        try {
            //创建索引
            CreateIndexRequest createRequest = new CreateIndexRequest("my_index_vec");

            //创建的每个索引都可以有与之关联的特定设置。
            createRequest.settings(Settings.builder()
                    .put("index.number_of_shards", 2)
                    .put("index.number_of_replicas", 1)
                    .put("index.refresh_interval", "10s")
                    .put("knn", true)
            );
            // 创建索引时创建文档类型映射
            createRequest.mapping(
                            "{\n" +
                            "   \"properties\":  {\n" +
                            "   \"id\":  {\n" +
                            "       \"type\":  \"long\"\n" +
                            "   },\n" +
                            "   \"field_hnsw\":  {\n" +
                            "       \"type\":  \"bpack_vector\",\n" +
                            "       \"index_type\":  \"hnsw\",\n" +
                            "       \"dims\":  8,\n" +
                            "       \"space_type\":  \"l2\",\n" +
                            "       \"parameters\":  {\n" +
                            "           \"m\":  32,\n" +
                            "           \"ef_construction\":  256\n" +
                            "           }\n" +
                            "       }\n" +
                            "   }\n" +
                            "}",
                    XContentType.JSON);

            // 同步执行创建索引操作
            CreateIndexResponse createIndexResponse = client.indices().create(createRequest, RequestOptions.DEFAULT);
            System.out.println("create index successfully! response : " + createIndexResponse.toString());

            // 批次写入文档
            BulkRequest bulkRequest = new BulkRequest();
            for (int i = 0; i < 100; i++) {
                // 以XContentBuilder对象的形式提供，Elasticsearch 内部会帮我们生成JSON内容
                XContentBuilder jsonBuilder = XContentFactory.jsonBuilder();

                jsonBuilder.startObject();
                {
                    jsonBuilder.field("id", i);
                    jsonBuilder.field("field_hnsw", RandomVector(8));
                }
                jsonBuilder.endObject();
                bulkRequest.add(new IndexRequest("my_index_vec").source(jsonBuilder));
            }
            BulkResponse bulkResponse = client.bulk(bulkRequest, RequestOptions.DEFAULT);
            System.out.println("bulk success ! response : " + bulkResponse.toString());

            //数据写入后会过一定时间触发自动的refresh构建向量索引，手动执行refresh保证可以立即查询
            RefreshRequest refreshRequest = new RefreshRequest("my_index_vec");
            RefreshResponse refreshResponse = client.indices().refresh(refreshRequest, RequestOptions.DEFAULT);
            System.out.println("refresh success ! response : " + refreshResponse.toString());

            // 检索向量数据
            // 创建检索request
            Request request = new Request(
                    "POST",
                    "/my_index_vec/_search");
            // 配置请求体
            request.setEntity(new NStringEntity("{\n" +
                    "  \"size\": 5, \n" +
                    "  \"_source\": [\"id\"], \n" +
                    "  \"query\": {\n" +
                    "    \"knn\": { \n" +
                    "      \"field_hnsw\": { \n" +
                    "        \"vector\": [0.2, 0.3, 0.5, 0.6, 0.7, 0.8, 0.9 ,0.1], \n" +
                    "        \"k\": 10, \n" +
                    "        \"ef\": 256 \n" +
                    "      }\n" +
                    "    }\n" +
                    "  }\n" +
                    "}", ContentType.APPLICATION_JSON));
            // 发送检索请求
            Response response = restClient.performRequest(request);
            System.out.println(EntityUtils.toString(response.getEntity()));

            // 指定要删除的索引名称
            DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest("my_index_vec");
            // 执行删除索引操作
            AcknowledgedResponse deleteIndexResponse = client.indices().delete(deleteIndexRequest, RequestOptions.DEFAULT);
            System.out.println("delete index successfully! response : " + deleteIndexResponse.toString());
        } catch (IOException ioException) {
            // 异常处理。
            ioException.printStackTrace();
        } finally {
            // 在不需要使用client后，将client关闭。
            try {
                client.close();
                restClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    // 生成指定维度随机向量
    public static float[] RandomVector(int dim) {
        float[] vec = new float[dim];
        Random random = new Random();

        // 随机生成数组元素
        for (int i = 0; i < dim; i++) {
            vec[i] = random.nextFloat(1);
        }
        return vec;
    }
}
            

以上示例代码中带{}的参数需要替换为您具体业务的参数，详情请参见代码注释。

更多Java High Level REST Client的使用特性，请参见Java High Level REST Client官方文档。更多Java Low Level REST Client的使用特性，请参见Java Low Level REST Client官方文档。

Low Level REST Client

通过其他客户端访问Elasticsearch

百度智能云

Elasticsearch BES

Elasticsearch BES

Rest Client操作向量索引示例

准备工作

pom依赖

示例