Java code: Synchronize column information of postgresql table to Elasticsearch index mapping

The following is to synchronize the column information of the postgresql table to Elasticsearch, and use Elasticsearch's Java Advanced Client (Java High Level REST Client) to operate.

Java code example:

import org.apache.http.HttpHost;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.common.xcontent.json.JsonXContent;
import org.postgresql.jdbc.PgConnection;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class PostgreSQLToElasticsearch {
    
    
    public static void main(String[] args) {
    
    
        // PostgreSQL数据库连接配置
        String pgHost = "your_pg_host";
        int pgPort = your_pg_port;
        String pgDatabase = "your_pg_database";
        String pgUsername = "your_pg_username";
        String pgPassword = "your_pg_password";

        // Elasticsearch连接配置
        String esHost = "your_es_host";
        int esPort = your_es_port;

        // 创建PostgreSQL连接
        try (Connection conn = DriverManager.getConnection("jdbc:postgresql://" + pgHost + ":" + pgPort + "/" + pgDatabase, pgUsername, pgPassword)) {
    
    
            // 获取表的元数据信息
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT column_name, data_type FROM information_schema.columns WHERE table_name = 'your_table'");

            // 创建Elasticsearch连接
            RestHighLevelClient esClient = new RestHighLevelClient(RestClient.builder(new HttpHost(esHost, esPort, "http")));

            // 创建Elasticsearch索引
            String indexName = "your_index_name";
            String indexMapping = "{\"mappings\": {\"properties\": {}}}";

            esClient.indices().create(new CreateIndexRequest(indexName).source(indexMapping, XContentType.JSON), RequestOptions.DEFAULT);

            // 将PostgreSQL表的数据导入到Elasticsearch索引
            while (rs.next()) {
    
    
                String columnName = rs.getString("column_name");
                String dataType = rs.getString("data_type");

                // 处理bytea类型字段
                if (dataType.equals("bytea")) {
    
    
                    // 从PostgreSQL中获取bytea数据
                    PgConnection pgConn = conn.unwrap(PgConnection.class);
                    byte[] byteaValue = pgConn.getRawBinaryResultSet().getBytes(rs.getRow());
                    String binaryValue = new String(byteaValue);

                    // 创建Elasticsearch文档
                    IndexRequest request = new IndexRequest(indexName)
                            .source(JsonXContent.contentBuilder()
                                    .startObject()
                                    .field(columnName, binaryValue)
                                    .endObject());

                    esClient.index(request, RequestOptions.DEFAULT);
                } else {
    
    
                    // 从PostgreSQL中获取其他数据类型的值
                    String value = rs.getString(columnName);

                    // 创建Elasticsearch文档
                    IndexRequest request = new IndexRequest(indexName)
                            .source(JsonXContent.contentBuilder()
                                    .startObject()
                                    .field(columnName, value)
                                    .endObject());

                    esClient.index(request, RequestOptions.DEFAULT);
                }
            }

            // 关闭连接
            rs.close();
            stmt.close();
            conn.close();
            esClient.close();
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }
    }
}

Please note that the above Java code only provides a basic operation example, you need to make appropriate modifications and adjustments according to the actual situation. Also, in order for Java code to be able to connect to PostgreSQL and Elasticsearch, you need to pom.xmladd the corresponding dependencies in the project's file.

Example pom.xml file:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    
    <groupId>com.example</groupId>
    <artifactId>postgretoes</artifactId>
    <version>1.0-SNAPSHOT</version>
    
    <dependencies>
        <!-- PostgreSQL JDBC driver -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.23</version>
        </dependency>
        
        <!-- Elasticsearch Java High Level REST Client -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
           <version>7.15.1</version>
        </dependency>
        
        <!-- Apache HttpClient -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.13</version>
        </dependency>
    </dependencies>
</project>

Please add the above dependencies to your project's pom.xmlfile, and make appropriate version adjustments and other configurations according to actual needs.