Hibernate 3 with Spring

1. Overview

This article will focus on setting up Hibernate 3 with Spring – we’ll look at how to use both XML and Java configuration to set up Spring with Hibernate 3 and MySQL.

Update: this article is focused on Hibernate 3. If you’re looking for the current version of Hibernate – this is the article focused on it.

2. Java Spring Configuration for Hibernate 3

Setting up Hibernate 3 with Spring and Java config is straightforward:

import java.util.Properties;
import javax.sql.DataSource;
import org.apache.tomcat.dbcp.dbcp.BasicDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
import org.springframework.orm.hibernate3.HibernateTransactionManager;
import org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import com.google.common.base.Preconditions;

@Configuration
@EnableTransactionManagement
@PropertySource({ "classpath:persistence-mysql.properties" })
@ComponentScan({ "com.baeldung.spring.persistence" })
public class PersistenceConfig {

   @Autowired
   private Environment env;

   @Bean
   public AnnotationSessionFactoryBean sessionFactory() {
      AnnotationSessionFactoryBean sessionFactory = new AnnotationSessionFactoryBean();
      sessionFactory.setDataSource(restDataSource());
      sessionFactory.setPackagesToScan(new String[] { "com.baeldung.spring.persistence.model" });
      sessionFactory.setHibernateProperties(hibernateProperties());

      return sessionFactory;
   }

   @Bean
   public DataSource restDataSource() {
      BasicDataSource dataSource = new BasicDataSource();
      dataSource.setDriverClassName(env.getProperty("jdbc.driverClassName"));
      dataSource.setUrl(env.getProperty("jdbc.url"));
      dataSource.setUsername(env.getProperty("jdbc.user"));
      dataSource.setPassword(env.getProperty("jdbc.pass"));

      return dataSource;
   }

   @Bean
   @Autowired
   public HibernateTransactionManager transactionManager(SessionFactory sessionFactory) {
      HibernateTransactionManager txManager = new HibernateTransactionManager();
      txManager.setSessionFactory(sessionFactory);

      return txManager;
   }

   @Bean
   public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
      return new PersistenceExceptionTranslationPostProcessor();
   }

   Properties hibernateProperties() {
      return new Properties() {
         {
            setProperty("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));
            setProperty("hibernate.dialect", env.getProperty("hibernate.dialect"));
         }
      };
   }
}

Compared to the XML Configuration – described next – there is a small difference in the way one bean in the configuration access another. In XML there is no difference between pointing to a bean or pointing to a bean factory capable of creating that bean. Since the Java configuration is type-safe – pointing directly to the bean factory is no longer an option – we need to retrieve the bean from the bean factory manually:

txManager.setSessionFactory(sessionFactory().getObject());

3. XML Spring Configuration for Hibernate 3

Similarly, we can set up Hibernate 3 with XML config as well:

<context:property-placeholder location="classpath:persistence-mysql.properties" />

<bean id="sessionFactory" 
  class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="packagesToScan" value="com.baeldung.spring.persistence.model" />
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
            <prop key="hibernate.dialect">${hibernate.dialect}</prop>
        </props>
    </property>
</bean>

<bean id="dataSource" 
  class="org.apache.tomcat.dbcp.dbcp.BasicDataSource">
    <property name="driverClassName" value="${jdbc.driverClassName}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.user}" />
    <property name="password" value="${jdbc.pass}" />
</bean>

<bean id="txManager" 
  class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

<bean id="persistenceExceptionTranslationPostProcessor" 
  class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

Then, this XML file is bootstrapped into the Spring context using a @Configuration class:

@Configuration
@EnableTransactionManagement
@ImportResource({ "classpath:persistenceConfig.xml" })
public class PersistenceXmlConfig {
   //
}

For both types of configuration, the JDBC and Hibernate specific properties are stored in a properties file:

# jdbc.X
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring_hibernate_dev?createDatabaseIfNotExist=true
jdbc.user=tutorialuser
jdbc.pass=tutorialmy5ql
# hibernate.X
hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
hibernate.show_sql=false
hibernate.hbm2ddl.auto=create-drop

4. Spring, Hibernate and MySQL

The example above uses MySQL 5 as the underlying database configured with Hibernate – however, Hibernate supports several underlying SQL Databases.

4.1. The Driver

The Driver class name is configured via the jdbc.driverClassName property provided to the DataSource.

In the example above, it is set to com.mysql.jdbc.Driver from the mysql-connector-java dependency we defined in the pom, at the start of the article.

4.2. The Dialect

The Dialect is configured via the hibernate.dialect property provided to the Hibernate SessionFactory.

In the example above, this is set to org.hibernate.dialect.MySQL5Dialect as we are using MySQL 5 as the underlying Database. There are several other dialects supporting MySQL:

• org.hibernate.dialect.MySQL5InnoDBDialect – for MySQL 5.x with the InnoDB storage engine
• org.hibernate.dialect.MySQLDialect – for MySQL prior to 5.x
• org.hibernate.dialect.MySQLInnoDBDialect – for MySQL prior to 5.x with the InnoDB storage engine
• org.hibernate.dialect.MySQLMyISAMDialect – for all MySQL versions with the ISAM storage engine

Hibernate supports SQL Dialects for every supported Database.

5. Usage

At this point, Hibernate 3 is fully configured with Spring and we can inject the raw Hibernate SessionFactory directly whenever we need to:

public abstract class FooHibernateDAO{

   @Autowired
   SessionFactory sessionFactory;

   ...

   protected Session getCurrentSession(){
      return sessionFactory.getCurrentSession();
   }
}

6. Maven

To add the Spring Persistence dependencies to the pom, please see the Spring with Maven example – we’ll need to define both spring-context and spring-orm.

Continuing to Hibernate 3, the Maven dependencies are simple:

<dependency>
   <groupId>org.hibernate</groupId>
   <artifactId>hibernate-core</artifactId>
   <version>3.6.10.Final</version>
</dependency>

Then, to enable Hibernate to use its proxy model, we need javassist as well:

<dependency>
   <groupId>org.javassist</groupId>
   <artifactId>javassist</artifactId>
   <version>3.18.2-GA</version>
</dependency>

We’re going to use MySQL as our DB for this tutorial, so we’ll also need:

<dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>5.1.32</version>
   <scope>runtime</scope>
</dependency>

And finally, we will not be using the Spring data source implementation – the DriverManagerDataSource; instead, we’ll use a production-ready connection pool solution – Tomcat JDBC Connection Pool:

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-dbcp</artifactId>
    <version>7.0.55</version>
</dependency>

7. Conclusion

In this example, we configured Hibernate 3 with Spring – both with Java and XML configuration.