JDBC and MySQL

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Revision as of 22:40, 2 May 2018 by Zombielinux (talk | contribs) (→‎Running the program: Made note of required java versions for test script.)
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This document describes how to set up your Arch system so that MySQL databases can be accessed via Java programs.

Installation

Installing MySQL

Install a MySQL implementation.

To allow for network access, make sure that /etc/mysql/my.cnf has the following line commented out, as shown here:

#skip-networking

Then, start the MySQL service.

Installing JDBC

Install a JDBC driver according to your MySQL variant:

If you use the AUR packages, you will need to link the driver(s) to your JRE's external libraries directory, as follows:

For mariadb-jdbc:

# ln -s /usr/share/java/mariadb-jdbc/mariadb-java-client.jar /usr/lib/jvm/default-runtime/jre/lib/ext

For mysql-jdbc:

# ln -s /usr/share/java/mysql-jdbc/mysql-connector-java-bin.jar /usr/lib/jvm/default-runtime/jre/lib/ext

Testing

To access MySQL's command line tool, run:

$ mysql

Creating the test database

The following commands create a database test, and grant all privileges to user foo identified by password bar. Change the variables at your discretion.

create database test;
grant all privileges on test.* to user@localhost identified by "bar";
flush privileges;

Afterwards, use Ctrl + d to exit the command line tool.

Creating the test program

Use a text editor to create the file DBDemo.java with the following code in it. You will need to change the username and password accordingly.

import java.sql.*;

public class DBDemo {
  public static void main(String[] args) throws SQLException, ClassNotFoundException {
    // Load the JDBC driver
    Class.forName("org.mariadb.jdbc.Driver");
    System.out.println("Driver loaded");

    // Try to connect
    Connection connection = DriverManager.getConnection
      ("jdbc:mysql://localhost/test", "foo", "bar");

    System.out.println("It works!");

    connection.close();
  }
}

If using Oracle MySQL (as opposed to MariaDB), the above class name should be set to com.mysql.jdbc.Driver.

Running the program

To compile and run the program, execute:

You will need jre8-openjdk to execute javac located at /usr/bin/javac

$ javac DBDemo.java
$ java DBDemo

If all was configured correctly, you should see:

Driver loaded
It works!