opensearch-docs-cn/_clients/java.md

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Java client

The OpenSearch Java client allows you to interact with your OpenSearch clusters through Java methods and data structures rather than HTTP methods and raw JSON.

For example, you can submit requests to your cluster using objects to create indices, add data to documents, or complete some other operation using the client's built-in methods.

Setup

To start using the OpenSearch Java client, ensure that you have the following dependency in your project's pom.xml file:

<dependency>
  <groupId>org.opensearch.client</groupId>
  <artifactId>opensearch-java</artifactId>
  <version>0.1.0</version>
</dependency>

If you're using Gradle, add the following dependencies to your project.

dependencies {
    implementation 'org.opensearch.client:opensearch-rest-client: {{site.opensearch_version}}'
    implementation 'org.opensearch.client:opensearch-java:0.1.0'
}

You can now start your OpenSearch cluster.

The following example uses credentials that come with the default OpenSearch configuration. If you're using the OpenSearch Java client with your own OpenSearch cluster, be sure to change the code to use your own credentials.

Sample code

This section uses a class called IndexData, which is a simple Java class that stores basic data and methods. For your own OpenSearch cluster, you might find that you need a more robust class to store your data.

IndexData class

static class IndexData {
  private String firstName;
  private String lastName;

  public IndexData(String firstName, String lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }

  public String getFirstName() {
    return firstName;
  }

  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }

  public String getLastName() {
    return lastName;
  }

  public void setLastName(String lastName) {
    this.lastName = lastName;
  }

  @Override
  public String toString() {
    return String.format("IndexData{first name='%s', last name='%s'}", firstName, lastName);
  }
}

OpenSearch client example

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.opensearch.client.RestClient;
import org.opensearch.client.RestClientBuilder;
import org.opensearch.clients.base.RestClientTransport;
import org.opensearch.clients.base.Transport;
import org.opensearch.clients.json.jackson.JacksonJsonpMapper;
import org.opensearch.clients.opensearch.OpenSearchClient;
import org.opensearch.clients.opensearch._global.IndexRequest;
import org.opensearch.clients.opensearch._global.IndexResponse;
import org.opensearch.clients.opensearch._global.SearchResponse;
import org.opensearch.clients.opensearch.indices.*;
import org.opensearch.clients.opensearch.indices.put_settings.IndexSettingsBody;

import java.io.IOException;

public class OpenSearchClientExample {
  public static void main(String[] args) {
    try{
    System.setProperty("javax.net.ssl.trustStore", "/full/path/to/keystore");
    System.setProperty("javax.net.ssl.trustStorePassword", "password-to-keystore");

    //Only for demo purposes. Don't specify your credentials in code.
    final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
    credentialsProvider.setCredentials(AuthScope.ANY,
      new UsernamePasswordCredentials("admin", "admin"));

    //Initialize the client with SSL and TLS enabled
    RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200, "https")).
      setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
        @Override
        public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
        return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
        }
      }).build();
    Transport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
    OpenSearchClient client = new OpenSearchClient(transport);

    //Create the index
    String index = "sample-index";
    CreateRequest createIndexRequest = new CreateRequest.Builder().index(index).build();
    client.indices().create(createIndexRequest);

    //Add some settings to the index
    IndexSettings indexSettings = new IndexSettings.Builder().autoExpandReplicas("0-all").build();
    IndexSettingsBody settingsBody = new IndexSettingsBody.Builder().settings(indexSettings).build();
    PutSettingsRequest putSettingsRequest = new PutSettingsRequest.Builder().index(index).value(settingsBody).build();
    client.indices().putSettings(putSettingsRequest);

    //Index some data
    IndexData indexData = new IndexData("first_name", "Bruce");
    IndexRequest<IndexData> indexRequest = new IndexRequest.Builder<IndexData>().index(index).id("1").value(indexData).build();
    client.index(indexRequest);

    //Search for the document
    SearchResponse<IndexData> searchResponse = client.search(s -> s.index(index), IndexData.class);
    for (int i = 0; i< searchResponse.hits().hits().size(); i++) {
      System.out.println(searchResponse.hits().hits().get(i).source());
    }

    //Delete the document
    client.delete(b -> b.index(index).id("1"));

    // Delete the index
    DeleteRequest deleteRequest = new DeleteRequest.Builder().index(index).build();
    DeleteResponse deleteResponse = client.indices().delete(deleteRequest);

    restClient.close();
    } catch (IOException e){
      System.out.println(e.toString());
    } finally {
      try {
        if (client != null) {
          client.close();
        }
      } catch (IOException e) {
        System.out.println(e.toString());
      }
    }
  }
}