Spring Hibernate Integration Example

                         Spring is one of the most used Java EE Framework and Hibernate is the most popular ORM framework. That’s why Spring Hibernate combination is used a lot in enterprise applications.

Spring Hibernate

Today in this tutorial, we will use Spring 4 and integrate it with Hibernate 3 and then update the same project to use Hibernate 4. Since there are a lot of versions for Spring and Hibernate both and Spring ORM artifact supports both Hibernate 3 and Hibernate 4, it’s good that I list all the dependencies I have used in my project.

Note that I have noticed that all spring and hibernate versions are not compatible, below versions have worked for me so I think they are compatible. If you are using some other versions and getting java.lang.NoClassDefFoundError, then it means that they are not compatible. Mostly it’s because Hibernate classes are moved from one package to another causing this error. For example org.hibernate.engine.FilterDefinition class is moved to org.hibernate.engine.spi.FilterDefinition in latest hibernate versions.

• Spring Framework Version: 4.0.3.RELEASE
• Hibernate Core and Hibernate EntityManager Version: 3.6.9.Final and 4.3.5.Final
• Spring ORM Version: 4.0.3.RELEASE

Database Setup

I am using MySQL database for my project, so below setup.sql script will create the necessary table for this example.

CREATE TABLE `Person` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL DEFAULT '',
  `country` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
commit;

Spring Hibernate Integration Example Project Structure

Below image shows the final project structure, we will go through each of the components one by one.

Maven Dependencies

We will first look into our pom.xml file for all the required dependencies and their versions.

<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>org.springframework.samples</groupId>
 <artifactId>SpringHibernateExample</artifactId>
 <version>0.0.1-SNAPSHOT</version>

 <properties>

  <!-- Generic properties -->
  <java.version>1.6</java.version>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

  <!-- Spring -->
  <spring-framework.version>4.0.3.RELEASE</spring-framework.version>

  <!-- Hibernate / JPA -->
  <!-- <hibernate.version>4.3.5.Final</hibernate.version> -->
  <hibernate.version>3.6.9.Final</hibernate.version>

  <!-- Logging -->
  <logback.version>1.0.13</logback.version>
  <slf4j.version>1.7.5</slf4j.version>

 </properties>

 <dependencies>
  <!-- Spring and Transactions -->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-context</artifactId>
   <version>${spring-framework.version}</version>
  </dependency>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-tx</artifactId>
   <version>${spring-framework.version}</version>
  </dependency>

  <!-- Spring ORM support -->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-orm</artifactId>
   <version>${spring-framework.version}</version>
  </dependency>

  <!-- Logging with SLF4J & LogBack -->
  <dependency>
   <groupId>org.slf4j</groupId>
   <artifactId>slf4j-api</artifactId>
   <version>${slf4j.version}</version>
   <scope>compile</scope>
  </dependency>
  <dependency>
   <groupId>ch.qos.logback</groupId>
   <artifactId>logback-classic</artifactId>
   <version>${logback.version}</version>
   <scope>runtime</scope>
  </dependency>

  <!-- Hibernate -->
  <dependency>
   <groupId>org.hibernate</groupId>
   <artifactId>hibernate-entitymanager</artifactId>
   <version>${hibernate.version}</version>
  </dependency>
  <dependency>
   <groupId>org.hibernate</groupId>
   <artifactId>hibernate-core</artifactId>
   <version>${hibernate.version}</version>
  </dependency>

  <dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>5.1.9</version>
  </dependency>
  <dependency>
   <groupId>commons-dbcp</groupId>
   <artifactId>commons-dbcp</artifactId>
   <version>1.4</version>
  </dependency>
 </dependencies>
</project>

Important Dependencies for Spring and Hibernate Integration Project are:

• spring-context and spring-tx for core Spring functionalities. Notice that I am using version 4.0.3.RELEASE.
• spring-orm dependency for Spring ORM support, it’s required for hibernate integration in our spring project.
• hibernate-entitymanager and hibernate-core dependencies for Hibernate framework. Notice that version is 3.6.9.Final, for using Hibernate 4 all we need is to change it to 4.3.5.Final as commented in above pom.xml file.
• mysql-connector-java for MySQL driver for database connection.

Model Class or Entity Bean

We can use Hibernate XML based mapping as well as JPA annotation based mapping. Here I am using JPA annotations for mapping because hibernate provides JPA implementation.

package com.learnsoftware.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

/**
 * Entity bean with JPA annotations
 * Hibernate provides JPA implementation
 * @author pankaj
 *
 */
@Entity
@Table(name="Person")
public class Person {

 @Id
 @Column(name="id")
 @GeneratedValue(strategy=GenerationType.IDENTITY)
 private int id;
 
 private String name;
 
 private String country;

 public int getId() {
  return id;
 }

 public void setId(int id) {
  this.id = id;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public String getCountry() {
  return country;
 }

 public void setCountry(String country) {
  this.country = country;
 }
 
 @Override
 public String toString(){
  return "id="+id+", name="+name+", country="+country;
 }
}

DAO Classes

We will implement two methods in our DAO classes, first to save the Person object into table and second that will fetch all the records from the table and returns the list of Persons.

package com.learnsoftware.dao;

import java.util.List;

import com.journaldev.model.Person;

public interface PersonDAO {

 public void save(Person p);
 
 public List<Person> list();
 
}

Above DAO class implementation would be like below.

package com.learnsoftware.dao;

import java.util.List;

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

import com.learnsoftware.model.Person;

public class PersonDAOImpl implements PersonDAO {

 private SessionFactory sessionFactory;

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }
    
 @Override
 public void save(Person p) {
  Session session = this.sessionFactory.openSession();
  Transaction tx = session.beginTransaction();
  session.persist(p);
  tx.commit();
  session.close();
 }

 @SuppressWarnings("unchecked")
 @Override
 public List<Person> list() {
  Session session = this.sessionFactory.openSession();
  List<Person> personList = session.createQuery("from Person").list();
  session.close();
  return personList;
 }

}

Notice that this is the only place where we are using Hibernate related classes. This pattern makes our implementation flexible and easy to migrate from one technology to another. For example, if we want to use iBatis ORM framework, all we need is to provide a DAO implementation for iBatis and then change the spring bean configuration file.

In above example, I am using Hibernate session transaction management. But we can also use Spring declarative transaction management using @Transactional annotation, read more at Spring Transaction Management.

Spring Bean Configuration File for Hibernate 3 Integration

Let’s first look at the spring bean configurations we need for Hibernate 3 integration, we will look into detail later on.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
 xmlns:tx="http://www.springframework.org/schema/tx"
 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
  http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
  http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

 <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
  destroy-method="close">
  <property name="driverClassName" value="com.mysql.jdbc.Driver" />
  <property name="url" value="jdbc:mysql://localhost:3306/TestDB" />
  <property name="username" value="pankaj" />
  <property name="password" value="pankaj123" />
 </bean>

<!-- Hibernate 3 XML SessionFactory Bean definition-->
<!--  <bean id="hibernate3SessionFactory"
  class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  <property name="dataSource" ref="dataSource" />
  <property name="mappingResources">
   <list>
    <value>person.hbm.xml</value>
   </list>
  </property>
  <property name="hibernateProperties">
   <value>
    hibernate.dialect=org.hibernate.dialect.MySQLDialect
   </value>
  </property>
 </bean> -->

<!-- Hibernate 3 Annotation SessionFactory Bean definition-->
 <bean id="hibernate3AnnotatedSessionFactory"
  class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
  <property name="dataSource" ref="dataSource" />
  <property name="annotatedClasses">
   <list>
    <value>com.journaldev.model.Person</value>
   </list>
  </property>
  <property name="hibernateProperties">
   <props>
    <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
    <prop key="hibernate.current_session_context_class">thread</prop>
    <prop key="hibernate.show_sql">false</prop>
   </props>
  </property>
 </bean>
 
 <bean id="personDAO" class="com.journaldev.dao.PersonDAOImpl">
  <property name="sessionFactory" ref="hibernate3AnnotatedSessionFactory" />
 </bean>
</beans>

There are two ways we can provide database connection details to Hibernate, first by passing everything in hibernateProperties and second by creating a DataSource and then passing it to hibernate. I prefer the second approach, that’s why we have Apache Commons DBCP dependency to create a BasicDataSourceby setting database connection properties.

For Spring and Hibernate 3 integration, Spring ORM provides two classes – org.springframework.orm.hibernate3.LocalSessionFactoryBean when hibernate mappings are XML based and org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean for annotations based mapping. I have provided simple bean configuration of LocalSessionFactoryBean in comments, if you are using XML based mappings. AnnotationSessionFactoryBean extends LocalSessionFactoryBean class, so it has all the basic properties for hibernate integration.

The properties are self understood and mostly hibernate related, so I will not go into much detail for them. But if you are wondering from where hibernateProperties, annotatedClasses are coming, you need to look into the bean class source code.

Notice the bean definition of personDAO, like I said earlier if we have to switch to some other ORM framework, we need to change the implementation class here and set any other properties we need.

Spring 4 Hibernate 3 Test Program

Our setup is ready now, let’s write a simple program to test our application.

package com.learnsoftware.main;

import java.util.List;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.journaldev.dao.PersonDAO;
import com.journaldev.model.Person;

public class SpringHibernateMain {

 public static void main(String[] args) {

  ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
  
  PersonDAO personDAO = context.getBean(PersonDAO.class);
  
  Person person = new Person();
  person.setName("Pankaj"); person.setCountry("India");
  
  personDAO.save(person);
  
  System.out.println("Person::"+person);
  
  List<Person> list = personDAO.list();
  
  for(Person p : list){
   System.out.println("Person List::"+p);
  }
  //close resources
  context.close(); 
 }
}

When we execute above program, we get a lot of output related to Hibernate because I haven’t setup logging properly, but that’s out of scope of this tutorial. However we get following output generated by our program.

Person::id=3, name=Pankaj, country=India
Person List::id=1, name=Pankaj, country=India
Person List::id=2, name=Pankaj, country=India
Person List::id=3, name=Pankaj, country=India

Spring 4 Hibernate 4 integration changes

Now let’s change our application to use Hibernate 4 instead of Hibernate 3. For this migration, we need to make only following configuration changes

1. Change the hibernate version to 4.3.5.Final in the pom.xml file, as shown in comments above.
2. Change the spring bean configuration file, till now you must have figured out that Spring bean configuration file is the key for integration of spring and hibernate framework. Below spring bean configuration file will work for Spring 4 and Hibernate 4 versions.

1. <?xml version="1.0" encoding="UTF-8"?>
   <beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
   
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
     destroy-method="close">
     <property name="driverClassName" value="com.mysql.jdbc.Driver" />
     <property name="url" value="jdbc:mysql://localhost:3306/TestDB" />
     <property name="username" value="pankaj" />
     <property name="password" value="pankaj123" />
    </bean>
   
   
   <!-- Hibernate 4 SessionFactory Bean definition -->
   <bean id="hibernate4AnnotatedSessionFactory"
     class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
     <property name="dataSource" ref="dataSource" />
     <property name="annotatedClasses">
      <list>
       <value>com.journaldev.model.Person</value>
      </list>
     </property>
     <property name="hibernateProperties">
      <props>
       <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
       <prop key="hibernate.current_session_context_class">thread</prop>
       <prop key="hibernate.show_sql">false</prop>
      </props>
     </property>
    </bean>
   
    
    <bean id="personDAO" class="com.journaldev.dao.PersonDAOImpl">
     <property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
    </bean>
   </beans>
   

                                                                                                                                                For hibernate 4, we need use org.springframework.orm.hibernate4.LocalSessionFactoryBeanfor SessionFactory bean, Spring ORM has merged both the classes for Hibernate 3 and there is a single class now, this is good to avoid confusion. All the other configurations are same as before.

That’s it, our project is successfully migrated to Hibernate 4, neat isn’t it. Just change the SpringHibernateMain class to use spring4.xml for beans configuration and it will work fine, you will get same output as before.