This example presents the basic concept of using PersistenceUnit in Spring.

The technologies used are :

– Spring 4.3.18
– H2 1.3
– Lombok 1.18
– JDK 1.80
– Maven 3.3.9

You can convert this example to an Eclipse IDE project by going to folder where is the pom.xml is, and use the command :

mvn eclipse:eclipse

Inspired from « Beginning Spring » Mert Caliskan, Kenan Sevindik, Rod Johnson (Foreword by), Jürgen Höller (Foreword by).

<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>javaspringexamples.springJPA</groupId>
	<artifactId>springJPAPersistenceUnit</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<properties>
		<maven.compiler.source>1.8</maven.compiler.source>
		<maven.compiler.target>1.8</maven.compiler.target>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>4.3.18.RELEASE</version>
		</dependency>

		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>4.3.18.RELEASE</version>
		</dependency>

		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-core</artifactId>
			<version>4.3.1.Final</version>
		</dependency>

		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-entitymanager</artifactId>
			<version>4.3.1.Final</version>
		</dependency>

		<dependency>
			<groupId>com.h2database</groupId>
			<artifactId>h2</artifactId>
			<version>1.3.175</version>
		</dependency>
	</dependencies>
</project>

package javaspringexamples.springJPA.PersistenceUnit;

import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.hibernate.jpa.HibernatePersistenceProvider;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;

@Configuration
public class Conf {

	@Bean
	public DataSource dataSource() {
		DriverManagerDataSource dataSource = new DriverManagerDataSource();
		dataSource.setDriverClassName("org.h2.Driver");
		dataSource.setUrl("jdbc:h2:tcp://localhost/~/javaspringexamples");
		dataSource.setUsername("sa");
		dataSource.setPassword("");
		return dataSource;
	}

	private Map<String, ?> jpaProperties() {
		Map<String, String> jpaPropertiesMap = new HashMap<String, String>();
		jpaPropertiesMap.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
		jpaPropertiesMap.put("hibernate.hbm2ddl.auto", "update");
		return jpaPropertiesMap;
	}

	@Bean
	public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
		LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean();
		factoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
		factoryBean.setDataSource(dataSource());
		factoryBean.setPackagesToScan("javaspringexamples.springJPA.PersistenceUnit");
		factoryBean.setJpaPropertyMap(jpaProperties());
		return factoryBean;
	}

	@Bean
	public PersonDAO personDao() {
		PersonDAOImpl dao = new PersonDAOImpl();
		return dao;
	}

}

package javaspringexamples.springJPA.PersistenceUnit;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

/**
 * 
 * @author mounir.sahrani@gmail.com
 *
 */
public class Main {

	public static void main(String[] args) {
		ApplicationContext applicationContext = new AnnotationConfigApplicationContext(Conf.class);

		PersonDAO dao = (PersonDAO) applicationContext.getBean("personDao");
		// Creating person object
		Person person = new Person();
		person.setFirstName("Jabane");
		person.setLastName("KOLOBANE");
		// Saving person
		dao.save(person);
	}
}

package javaspringexamples.springJPA.PersistenceUnit;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

/**
 * 
 * @author mounir.sahrani@gmail.com
 *
 */
@Entity
public class Person {

	@Id
	@GeneratedValue
	private Long id;

	private String firstName;

	private String lastName;

	public Long getId() {
		return id;
	}

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}
}

package javaspringexamples.springJPA.PersistenceUnit;

/**
 * 
 * @author mounir.sahrani@gmail.com
 *
 */
public interface PersonDAO {
	public void save(Person p);
}

package javaspringexamples.springJPA.PersistenceUnit;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.PersistenceUnit;

/**
 * 
 * @author mounir.sahrani@gmail.com
 *
 */

public class PersonDAOImpl implements PersonDAO {

	@PersistenceUnit
	private EntityManagerFactory emf;

	public void save(Person p) {
		EntityManager em = emf.createEntityManager();
		EntityTransaction transaction = em.getTransaction();
		transaction.begin();
		em.persist(p);
		transaction.commit();
		em.close();
	}
}

Get the sources of the example from the following GitHub url

Or Download a .zip file