lazy loading with hibernate

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

Code:

---

<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

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

Code:

---

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

---

Please help...
Thanks,
SSSS.

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:

Code:

---

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

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

---

clean up:

Code:

---

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

session.flush();

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

---

regards,
Mario

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