全部產品
Search
文件中心

Lindorm:Java Low Level REST Client

更新時間:Jul 06, 2024

Java Low Level REST Client是Elasticsearch官方提供的低層級REST用戶端,其API不負責資料的編碼與解碼。Lindorm搜尋引擎相容Elasticsearch 7.10及更早版本的功能,如果您想要自訂請求和響應處理方式,可以通過Java Low Level REST Client串連並使用搜尋引擎。

前提條件

  • 已安裝Java環境,要求安裝JDK 1.8及以上版本。

  • 已開通搜尋引擎。如何開通,請參見開通指南

  • 已將用戶端IP地址添加至Lindorm白名單,具體操作請參見設定白名單

操作步驟

  1. 安裝Low Level Rest Client。以Maven專案為例,在pom.xml檔案的dependencies中添加依賴項。範例程式碼如下:

    <dependency>
      <groupId>org.elasticsearch.client</groupId>
      <artifactId>elasticsearch-rest-client</artifactId>
      <version>7.10.0</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
      <version>2.8.2</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>2.7</version>
    </dependency>
  2. 配置串連參數。

    //Lindorm搜尋引擎的Elasticsearch相容地址
    String search_url = "ld-t4n5668xk31ui****-proxy-search-public.lindorm.rds.aliyuncs.com";
    int search_port = 30070;
    
    // 配置使用者名稱密碼
    String username = "user";
    String password = "test";
    final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
    credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(username, password));
    RestClientBuilder restClientBuilder = RestClient.builder(new HttpHost(search_url, search_port));
    restClientBuilder.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
      @Override
      public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
        return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
      }
    });

    參數說明

    參數

    說明

    search_url

    Lindorm搜尋引擎的Elasticsearch相容地址。如何擷取,請參見查看串連地址

    重要
    • 如果應用部署在ECS執行個體,建議您通過專用網路訪問Lindorm執行個體,可獲得更高的安全性和更低的網路延遲。

    • 如果應用部署在本地,在通過公網串連Lindorm執行個體前,需在控制台開通公網地址。開通方式:在控制台的左側導覽列,選擇資料庫連接,單擊搜尋引擎頁簽,在頁簽右上方單擊開通公網地址

    • 通過專用網路訪問Lindorm執行個體,search_url請填寫Elasticsearch相容地址對應的專用網路地址。通過公網訪問Lindorm執行個體,search_url請填寫Elasticsearch相容地址對應的公網地址。

    search_port

    Lindorm搜尋引擎Elasticsearch相容的連接埠,固定為30070。

    username

    訪問搜尋引擎的使用者名稱和密碼。

    預設使用者名和密碼的擷取方式:在控制台的左側導覽列,選擇資料庫連接,單擊搜尋引擎頁簽,在搜尋引擎頁簽可擷取。

    password

  3. 使用Java Low Level REST Client對象訪問搜尋引擎。

    範例程式碼分為以下幾部分:

    • 建立搜尋索引:建立搜尋索引lindorm_index。

    • 資料寫入:使用批量資料寫入的方式,寫入5000條文檔。

    • 資料查詢:重新整理請求,強制寫入的資料可見。執行兩個請求,分別查詢索引中的全部文檔和ID為特定值的文檔。

    • 資料刪除:刪除ID為test的文檔,並刪除索引lindorm_index。

    try (RestClient restClient = restClientBuilder.build()) {
      String indexName = "lindorm_index";
    
      // 建立索引
      Request indexRequest = new Request("PUT", "/" + indexName);
      indexRequest.setJsonEntity("{" +
        "  \"settings\":{" +
        "    \"index.number_of_shards\": 1" +
        "  }," +
        "  \"mappings\":{" +
        "    \"properties\":{" +
        "      \"name\":{" +
        "        \"type\":\"text\"" +
        "      }" +
        "    }" +
        "  }" +
        "}");
      Response response = restClient.performRequest(indexRequest);
      String responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);
    
      // 批量寫入資料
      Random random = new Random();
      Request bulkRequest = new Request("POST", "/_bulk");
      StringBuilder bulkJsonBuilder = new StringBuilder();
      for (int i = 0; i < 5000; i++) {
        // 請將field和value替換為實際業務欄位與值
        bulkJsonBuilder.append("{\"index\":{\"_index\":\"").append(indexName).append("\",\"_id\":\"").append(i).append("\"}}").append("\n");
        String value = random.nextInt() + "";
        bulkJsonBuilder.append("{\"field1\":\"").append(value).append("\",\"field2\":\"").append(value).append("\"}").append("\n");
      }
      bulkRequest.setJsonEntity(bulkJsonBuilder.toString());
      response = restClient.performRequest(bulkRequest);
    
      // 發送重新整理請求,強制已寫資料可見
      response = restClient.performRequest(new Request("POST", "/" + indexName + "/_refresh"));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);
    
      // 查詢索引中所有資料,預設最多返回10條查詢結果
      response = restClient.performRequest(new Request("GET", "/" + indexName + "/_search"));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);
    
      // 查詢索引中文檔id為"0"的資料
      response = restClient.performRequest(new Request("GET", "/" + indexName + "/_doc/0"));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);
    
      // 刪除索引
      response = restClient.performRequest(new Request("DELETE", "/" + indexName));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);
    
    } catch (Exception e) {
      System.out.println("msg: " + e.getMessage());
    }

完整樣本

完整範例程式碼如下:

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.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;

import org.apache.http.util.EntityUtils;
import org.elasticsearch.client.Request;
import org.elasticsearch.client.Response;

import java.util.Random;

public class RestLClientTest {
  public static void main(String[] args) {
    // Lindorm搜尋引擎的Elasticsearch相容地址
    String search_url = "ld-t4n5668xk31ui****-proxy-search-public.lindorm.rds.aliyuncs.com";
    int search_port = 30070;

    // 配置使用者名稱密碼
    String username = "user";
    String password = "test";

    final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
    credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(username, password));
    RestClientBuilder restClientBuilder = RestClient.builder(new HttpHost(search_url, search_port));
    restClientBuilder.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
      @Override
      public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
        return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
      }
    });

    try (RestClient restClient = restClientBuilder.build()) {
      String indexName = "lindorm_index";

      // 建立索引
      Request indexRequest = new Request("PUT", "/" + indexName);
      indexRequest.setJsonEntity("{" +
        "  \"settings\":{" +
        "    \"index.number_of_shards\": 1" +
        "  }," +
        "  \"mappings\":{" +
        "    \"properties\":{" +
        "      \"name\":{" +
        "        \"type\":\"text\"" +
        "      }" +
        "    }" +
        "  }" +
        "}");
      Response response = restClient.performRequest(indexRequest);
      String responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);

      // 批量寫入資料
      Random random = new Random();
      Request bulkRequest = new Request("POST", "/_bulk");
      StringBuilder bulkJsonBuilder = new StringBuilder();
      for (int i = 0; i < 5000; i++) {
        // 請將field和value替換為實際業務欄位與值
        bulkJsonBuilder.append("{\"index\":{\"_index\":\"").append(indexName).append("\",\"_id\":\"").append(i).append("\"}}").append("\n");
        String value = random.nextInt() + "";
        bulkJsonBuilder.append("{\"field1\":\"").append(value).append("\",\"field2\":\"").append(value).append("\"}").append("\n");
      }
      bulkRequest.setJsonEntity(bulkJsonBuilder.toString());
      response = restClient.performRequest(bulkRequest);

      // 發送重新整理請求,強制已寫資料可見
      response = restClient.performRequest(new Request("POST", "/" + indexName + "/_refresh"));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);

      // 查詢索引中所有資料,預設最多返回10條查詢結果
      response = restClient.performRequest(new Request("GET", "/" + indexName + "/_search"));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);

      // 查詢索引中文檔id為"0"的資料
      response = restClient.performRequest(new Request("GET", "/" + indexName + "/_doc/0"));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);

      // 刪除索引
      response = restClient.performRequest(new Request("DELETE", "/" + indexName));
      responseBody = EntityUtils.toString(response.getEntity());
      System.out.println("responseBody = " + responseBody);

    } catch (Exception e) {
      System.out.println("msg: " + e.getMessage());
    }
  }
}

執行成功後將返回如下結果:

responseBody = {"acknowledged":true,"shards_acknowledged":true,"index":"lindorm_index"}
responseBody = {"_shards":{"total":1,"successful":1,"failed":0}}
responseBody = {"took":6,"timed_out":false,"_shards":{"total":1,"successful":1,"skipped":0,"failed":0},"hits":{"total":{"value":5000,"relation":"eq"},"max_score":1.0,"hits":[{"_index":"lindorm_index","_id":"0","_score":1.0,"_source":{"field1":"2127821774","field2":"2127821774"}},{"_index":"lindorm_index","_id":"1","_score":1.0,"_source":{"field1":"1820331840","field2":"1820331840"}},{"_index":"lindorm_index","_id":"2","_score":1.0,"_source":{"field1":"-388903172","field2":"-388903172"}},{"_index":"lindorm_index","_id":"3","_score":1.0,"_source":{"field1":"-68048869","field2":"-68048869"}},{"_index":"lindorm_index","_id":"4","_score":1.0,"_source":{"field1":"1865955199","field2":"1865955199"}},{"_index":"lindorm_index","_id":"5","_score":1.0,"_source":{"field1":"1088273523","field2":"1088273523"}},{"_index":"lindorm_index","_id":"6","_score":1.0,"_source":{"field1":"-1529281106","field2":"-1529281106"}},{"_index":"lindorm_index","_id":"7","_score":1.0,"_source":{"field1":"-1185412160","field2":"-1185412160"}},{"_index":"lindorm_index","_id":"8","_score":1.0,"_source":{"field1":"-1243760053","field2":"-1243760053"}},{"_index":"lindorm_index","_id":"9","_score":1.0,"_source":{"field1":"1066058716","field2":"1066058716"}}]}}
responseBody = {"_index":"lindorm_index","_id":"0","_version":1,"_seq_no":0,"_primary_term":1,"found":true,"_source":{"field1":"2127821774","field2":"2127821774"}}
responseBody = {"acknowledged":true}