Java代码：将postgresql表的列信息同步到Elasticsearch索引映射

￡神魔★判官ぃ 2023-10-14 22:03 6阅读 0赞

以下是将postgresql表的列信息同步到Elasticsearch，使用Elasticsearch的Java高级客户端（Java High Level REST Client）进行操作。

Java代码示例：

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();
            }
        }
    }

请注意，上述Java代码仅提供了基本的操作示例，您需要根据实际情况进行适当的修改和调整。另外，为了使Java代码能够连接到PostgreSQL和Elasticsearch，您需要在项目的 `pom.xml` 文件中添加相应的依赖项。

pom.xml文件示例：

<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>
            
            <dependency>
                <groupId>org.postgresql</groupId>
                <artifactId>postgresql</artifactId>
                <version>42.2.23</version>
            </dependency>
            
            
            <dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>elasticsearch-rest-high-level-client</artifactId>
               <version>7.15.1</version>
            </dependency>
            
            
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.13</version>
            </dependency>
        </dependencies>
    </project>

请将上述依赖项添加到您的项目的 `pom.xml` 文件中，并根据实际需要进行适当的版本调整和其他配置。