how to open session for query execution in Hibernate - spring

Question

I am using struts2-spring-hibernate in my project.
I am handling the DB connection through spring, so I dont need of hibernate.cfg.xml
I need to execute my query and I need the result
I am successfully getting the result, by using these methods
Mannually open and close the session:
1. Session session = sessionFactory.openSession();
2. Session newSession = HibernateUtil.getSessionFactory().openSession();
Not handling the session mannually
1. getHibernateTemplate().find();
2. getSession().createSQLQuery();
I dont know which method is best one, please suggest me, which one is best for session
when the session will open and close by getHibernateTemplate() and getSession().

Answer 1

I will show the way I use these frameworks together. I avoid the need of HibernateTemplate, I reckon this class is too limited, I prefer to use the Session directly.
Once you have Spring in your project, it should inject the Hibernate SessionFactory in your Daos, so you can handle the Session. First of all, you need to configure the SessionFactory in your applicationContext.xml:
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation">
<value>classpath:hibernate.cfg.xml</value>
</property>
</bean>
Now you can inject the SessionFactory with the #Autowired annotation:
#Repository
public class HibernateProductDao implements ProductDao {
private final SessionFactory factory;
#Autowired
public HibernateProductDao(final SessionFactory factory) {
this.factory = factory;
}
public List<Product> findAll() {
return factory.getCurrentSession().createCriteria(Product.class).list();
}
public void add(final Product product) {
factory.getCurrentSession().save(product);
}
}
There are here some important thing, you should use the method getCurrentSession() because this way you allow Spring to control the Session lifecycle. If you use getSession() instead, it become your responsability, for instance, close the Session.
Now, let's configure Struts 2. In your web.xml:
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
You need the file struts.xml too, to say that Spring will fabricate the objects:
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<constant name="struts.objectFactory" value="spring" />
</struts>
Finally, you can inject the Dao in your action:
public class ProductAction {
private ProductDao dao;
#Autowired
public ProductAction(ProductDao dao) {
this.dao = dao;
}
}
Of course, since you're using Spring annotations, you need to scan the packages with component-scan.
That's the best way I found to integrate this frameworks, I hope it's helpful.