Using Hibernate In Standalone App (without Spring) using MariaDB

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So recently I need to set up a quick project to store the results of my crawler in a database. Previously, I would use JDBC for this job. However, with the recent knowledge of Hibernate, why don’t I give it a go?

In this post, I’m going to show you how you can use Hibernate to store entities just like you can with frameworks like Spring but on a standalone app (commandline app/Desktop app such as JavaFX).

The application will save an entity Book into a database called book_db

Quick MariaDB setup

To quickly set up a MariaDB database, I use the following docker-compose file. I use mariadb:10.5 and PHPMyAdmin for easy access to the database. If you prefer, you can skip using PHPMyAdmin and use another version of MariaDB:

version: "3"
services:
  db:
    image: mariadb:10.5
    container_name: db
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - MYSQL_DATABASE=speech_db
    restart: always
    ports:
    - 13308:3306
    volumes:
      - mysql_vol:/var/lib/mysql
  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    container_name: phpmyadmin
    environment:
      - PMA_HOST=db
      - PMA_PORT=3306
    restart: always
    ports:
      - 18811:80
volumes:
  mysql_vol:

Now, simply run docker-compose up -d, you have a fully functional MariaDB instance up and running.

Import Hibernates and other convenient libraries using Maven

Here is the dependency section in pom.xml

    <dependencies>


        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.5.7.Final</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.12</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

Other than hibernate and MySQL connector, the other are optional.

Create hibernate.cfg.xml to setup database connection

The next step would be to create a hibernate.cfg.xml file to configure the connection to the database. Where should you put this file? It should be under resources directory like I have here:

In this file, you specify the db configuration like so:

<?xml version = "1.0" encoding = "utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>

        <property name = "hibernate.dialect">
            org.hibernate.dialect.MySQLDialect
        </property>

        <property name = "hibernate.connection.driver_class">
            com.mysql.jdbc.Driver
        </property>

        <!-- Assume test is the database name -->

        <property name = "hibernate.connection.url">
            jdbc:mysql://localhost:13308/book_db
        </property>

        <property name = "hibernate.connection.username">
            root
        </property>

        <property name = "hibernate.connection.password">
            root
        </property>
    </session-factory>
</hibernate-configuration>

Also, open phpMyadmin and create the following table:

Now the hard part is done. Let’s create some entities and save them to the database.

Actually save an entity to database

Let’s create an entity like this:

package entity;

import lombok.Getter;
import lombok.Setter;

import javax.persistence.*;

@Entity
@Setter
@Getter
@Table(name = "book")
public class Book {
    @Id
    @Column(name = "id", nullable = false)
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    String title;
    String author;
    int pages;

}

And to save the entity, we need a session, which provided by SessionFactory. Let’s create a class that provides SessionFactory

import entity.Book;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class SessionFactoryMaker {
    private static SessionFactory factory;

    private static void configureFactory()
    {
        try {
            factory = new Configuration()
                    .addAnnotatedClass(Book.class)
                    .configure().buildSessionFactory();
        } catch (Throwable ex) {
            System.err.println("Failed to create sessionFactory object." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static org.hibernate.SessionFactory getFactory() {
        if (factory == null) {
            configureFactory();
        }

        return factory;
    }

}

One very important line in this class is #12. It is very important that you add the entity to the configuration. Without this step, hibernate will not know Book is an entity.

Finally, let’s create a book and insert it:

import entity.Book;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;

public class Runner {
    public static void main(String[] args) {

        Book b = new Book();
        b.setAuthor("No name");
        b.setPages(2000);
        b.setTitle("Some book");
        
        SessionFactory factory = SessionFactoryMaker.getFactory();

        try (Session session = factory.openSession()) {
            Transaction tx = session.beginTransaction();
            session.save(b);
            tx.commit();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Running this would create a record in the database:

You can find the full repo here https://github.com/datmt/Hibernate-MariaDB-Standalone

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