Hibernate 5 + JPA 2 Configuration example


The Java Persistence API (a.k.a. JPA) is a Java specification for managing, persisting and accessing data between objects and relation database. Hibernate is a ORM (Object Relational Mapping) which implements JPA specification.

In this post, we will show you how to create or configure a simple JPA application with Hibernate.

Technologies and tools used for this application are -

  • Hibernate 5.2.6.Final
  • JPA 2.1
  • Eclipse Mars.2 (4.5.2)
  • Maven 3.3.9
  • JavaSE 1.8
  • MySQL 5.7.12

 

Project Structure

Review the following project structure.

Hibernate JPA Configuration - BORAJI.COM

Let's begin step by step…


Step 1 – Create a maven project

Refer this article to learn - How to create a maven project in eclipse.

 

Step 2 - Add jar dependencies to pom.xml

Open pom.xml file and add required Hibernate and MySQL connector dependencies to it. Here is the pom.xml file.

pom.xml

<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.boraji.tutorial.hibernate</groupId>
  <artifactId>hibernate-jpa-example</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>hibernate-tutorial</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <!-- MySQL connector -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>6.0.5</version>
    </dependency>
    <!-- Hibernate 5.2.6 Final -->
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.2.6.Final</version>
    </dependency>
  </dependencies>

  <build>
    <sourceDirectory>src/main/java</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.5.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

 

Step 3 - Create a JPA configuration file

Create an XML file named as persistence.xml under src/main/java/META-INF folder and write the following code in it.

persistence.xml

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
  version="2.1">

  <persistence-unit name="PERSISTENCE">
    <description> Hibernate JPA Configuration Example</description>
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

    <properties>
      <property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver" />
      <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/BORAJI" />
      <property name="javax.persistence.jdbc.user" value="root" />
      <property name="javax.persistence.jdbc.password" value="admin" />
      <property name="hibernate.show_sql" value="true" />
      <property name="hibernate.hbm2ddl.auto" value="update" />
    </properties>

  </persistence-unit>

</persistence>

 

Step 4 - Create a JPA helper class

Create a helper class to bootstrap a JPA EntityManagerFactory.

JPAUtil.java

package com.boraji.tutorial.hibernate;

import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

/**
 * @author imssbora
 */
public class JPAUtil {
  private static final String PERSISTENCE_UNIT_NAME = "PERSISTENCE";
  private static EntityManagerFactory factory;

  public static EntityManagerFactory getEntityManagerFactory() {
    if (factory == null) {
      factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
    }
    return factory;
  }

  public static void shutdown() {
    if (factory != null) {
      factory.close();
    }
  }
}

 

Step 5 - Create a main class and run application

Here is the main class to check the database version using the EntityManager#createNativeQuery method.

MainApp.java

package com.boraji.tutorial.hibernate;

import javax.persistence.EntityManager;

/**
 * @author imssbora
 */
public class MainApp {
  public static void main(String[] args) {
    EntityManager entityManager = JPAUtil.getEntityManagerFactory().createEntityManager();
    entityManager.getTransaction().begin();

    // Check database version
    String sql = "select version()";

    String result = (String) entityManager.createNativeQuery(sql).getSingleResult();
    System.out.println(result);

    entityManager.getTransaction().commit();
    entityManager.close();

    JPAUtil.shutdown();
  }
}

Output

Hibernate: select version()
5.7.12-log

 

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