lazy loading with hibernate

[SSSS]

Hi,
I have a problem in lazy loading...follwing is my configuration...

<beans>	
	<bean id="dataSource"
		class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="driverClassName">
			<value>$&#123;hibernate.connection.driver_class&#125;</value>
		</property>
		<property name="url">
			<value>$&#123;hibernate.connection.url&#125;</value>
		</property>
		<property name="username">
			<value>$&#123;hibernate.connection.username&#125;</value>
		</property>
		<property name="password">
			<value>$&#123;hibernate.connection.password&#125;</value>
		</property>

	</bean>

	<!-- Hibernate SessionFactory -->
	<bean id="sessionFactory"
		class="org.springframework.orm.hibernate.LocalSessionFactoryBean">
		<property name="dataSource">
			<ref local="dataSource" />
		</property>

		<property name="mappingResources">
			<list>
				<value>
					com/testing/impl/Service.hbm.xml
				</value>
			</list>
		</property>
		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">
					$&#123;hibernate.dialect&#125;
				</prop>
			</props>
		</property>

	</bean>

	<!-- Transaction manager for a single Hibernate SessionFactory &#40;alternative to JTA&#41; -->
	<bean id="transactionManager"
		class="org.springframework.orm.hibernate.HibernateTransactionManager">
		<property name="sessionFactory">
			<ref local="sessionFactory" />
		</property>
	</bean>

	<!-- Add DAOs here -->
	<bean id="userDao"
		class="com.testing.dao.hibernate.HibernateRoleDAO">
		<property name="sessionFactory">
			<ref local="sessionFactory" />
		</property>
	</bean>

	<bean id="Service"
		class="org.springframework.aop.framework.ProxyFactoryBean">
		<property name="target">
			<ref bean="userManagerTarget" />
		</property>
		 <property name="proxyInterfaces">
           <value>com.testing.Service</value>
         </property>
		
		<property name="interceptorNames">
		<list>
			<value>hibernateInterceptor</value>
		</list>
	</property>
	</bean>

	  <bean id="hibernateInterceptor"
		class="org.springframework.orm.hibernate.HibernateInterceptor">
		<property name="sessionFactory">
			<ref bean="sessionFactory" />
		</property>
	</bean>


<bean id="userManagerTarget"
		class="com.testing.ServiceImpl">
	<property name="userDao">
		<ref bean="userDao" />
	</property>
</bean>

I am getting "Failed to lazily initialize a collection - no session or session was closed" exception with the following code

Service service = (Service) context.getBean("Service");
    	User[] users = service.getUsers();
    	System.out.println("name is " + users[0].getEmailAddress());
    	System.out.println("role name is " + users[0].getRoles()[0].getName()); // Getting the exception here

But this is what exactly was suggested in
http://www.jroller.com/page/kbaum/20040708

Then where am I doing wrong? Why am I not able to lazily load the objects?
Following is my DAO code

public List getUsers() throws DataAccessException {
        List users = (List) getHibernateTemplate().find("from User");
        return users;
    }

Please help...
Thanks,
SSSS.

[nyname00]

Hi,

for lazy loading to work in a webapp you will have to put a OpenSessionInViewFilter/OpenSessionInViewInterceptor into your web.xml.
If you're not in a webapp you will have to init it manually:

init:

SessionFactory sessionFactory = (SessionFactory) getBean("sessionFactory");

Session session = sessionFactory.openSession();
TransactionSynchronizationManager.bindResource(sessionFactory, new SessionHolder(session));

clean up:

SessionHolder holder = (SessionHolder) TransactionSynchronizationManager.getResource(sessionFactory);
Session session = holder.getSession();

session.flush();

TransactionSynchronizationManager.unbindResource(sessionFactory);
SessionFactoryUtils.closeSessionIfNecessary(session, sessionFactory);

regards,
Mario

[rjst]

Hi,

I'm using the OpenSessionInViewFilter, and still can't do lazy initialization from my views.

I tried the "manual" version you sugest from a test class, and it works.

I tried adding breakpoints to OpenSessionInViewFilter, and can see it gets the sessionFactory, opens the session, and binds it to the sessionFactory, but still it doesn't work.

I took a look at TransactionSynchronizationManager, and got the impression that for the OpenSessionInViewFilter to work I had to use transactions. Could this be the issue ?

thanks
Ricardo