Connecting to a Standard HTAP Instance Through JDBC

Precautions

Currently, HTAP instances only support the UTF-8 character set.

Prerequisites

• You are familiar with:
  • Computer basics
  • Java
  • JDBC knowledge

• You have downloaded the official JDBC driver for MySQL or MirrorDB.
• You have created a standard HTAP instance.
• The following dependency has been added to the pom.xml file.

  <dependency>   
      <groupId>mysql</groupId>   
      <artifactId>mysql-connector-java</artifactId>   
      <version>5.1.47</version> 
  </dependency>

• You can use the following command to connect to an HTAP instance through JDBC:

  jdbc:mysql://<instance_ip>:<instance_port>/<database_name>

  Parameter	Description
  <instance_ip>	IP address of the FE node in the HTAP instance. If a proxy is installed, use the IP address of the proxy.
  <instance_port>	HTAP instance port. The default value is 3306.
  <database_name>	Database name used for connecting to the instance.

Sample Code

Code example (Java code for connecting to an HTAP database):

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.SQLException;
public class JDBCTest {
    static final String IP = "*.*.*.*"; //IP address of the instance
    static final String USER = "***"; //Username
    static final String PASS = "***"; //Password
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        String url = "jdbc:clickhouse://" + IP + ":8123";
        try {
            
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(url, USER, PASS);
            stmt = conn.createStatement();
            String sql = "show databases;";
            ResultSet rs = stmt.executeQuery(sql);
            int columns = rs.getMetaData().getColumnCount();
            for (int i = 1; i <= columns; i++) {
                System.out.print(rs.getMetaData().getColumnName(i));
                System.out.print("\t");
            }
            while (rs.next()) {
                System.out.println();
                for (int i = 1; i <= columns; i++) {
                    System.out.print(rs.getObject(i));
                    System.out.print("\t");
                }
            }
            rs.close();
            stmt.close();
            conn.close();
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // release resource ....
        }
    }
}