How to @Autowire a SessionFactory to a Servlet?

Question

I am trying to @Autowire the SessionFactory in my GWT Servlet. What I tried first was loading it using the application context:

this.sessionFactory = (SessionFactory) applicationContext.getBean("sessionFactory");

but I guess that doesn't work that way if I want to use the @Transactional annotation. That's why I'm trying to auto wire it by telling Spring that sessionFactory is a property to be set over setSessionFactory(SessionFactory sessionFactory); but that does not work either somehow:

package com.mahlzeit.server.web.repository.impl;
// ..
@Component
public class RestaurantServiceImpl  extends XsrfProtectedServiceServlet implements RestaurantService {

    public RestauranOwnerRepository restaurantOwnerRepository;
    private SessionFactory sessionFactory;

    @Autowired 
    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory ;
    }

    @Override
    public void init(ServletConfig config) throws ServletException {

        super.init(config);

        @SuppressWarnings("resource") // Do not close application context!
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("/appServlet/servlet-context.xml");

        //this.sessionFactory = (SessionFactory) applicationContext.getBean("sessionFactory");
        this.restaurantOwnerRepository = (RestauranOwnerRepository)applicationContext.getBean("restaurantOwnerRepository");
    }

    @Transactional
    @Override
    public List<RestaurantDTO> getAvailableRestaurants() {
        List<Restaurant> availableRestaurants = restaurantOwnerRepository.getRestaurants(getSessionId());
        return ConvertEntity.converRestaurants(availableRestaurants);
    }
}

In my Spring servlet-context.xml I'm having:

<context:component-scan base-package="com.mahlzeit.server.web" />

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="configLocation" value="classpath:hibernate-webserver.cfg.xml" />
</bean>

<tx:annotation-driven/>
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

<bean id="restaurantServiceImpl" class="com.mahlzeit.server.web.service.restaurant.RestaurantServiceImpl">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

what I am getting is a org.hibernate.HibernateException :

Caused by: org.hibernate.HibernateException: Could not obtain transaction-synchronized Session for current thread
    at org.springframework.orm.hibernate4.SpringSessionContext.currentSession(SpringSessionContext.java:134)
    at org.hibernate.internal.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:988)
    at com.mahlzeit.server.web.repository.impl.RestaurantOwnerRepositoryImpl.get(RestaurantOwnerRepositoryImpl.java:42)
    at com.mahlzeit.server.web.repository.impl.RestaurantOwnerRepositoryImpl.getRestaurants(RestaurantOwnerRepositoryImpl.java:74)
    at com.mahlzeit.server.web.service.restaurant.RestaurantServiceImpl.getAvailableRestaurants(RestaurantServiceImpl.java:70)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:587)
    ... 25 more

Does anybody know how I can make this work? I found this but I'm not sure if that would work and besides that I am not sure if I want to extend the XsrfProtectedServiceServlet .

Thank you for any help!

Answer 1

Not familiar with GWT but I wouldn't implement the service in a Servlet. I would have a service layer and inject the bean in the servlet, this way you get a transaction ready service you can use:

public class RestaurantServlet extends HttpServet{
    @Autowired
    private RestaurantService service;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        WebApplicationContext ac = WebApplicationContextUtils.getRequiredWebApplicationContext(config.getServletContext());
        ac.getAutowireCapableBeanFactory().autowireBean(this);
    }
}

According to XsrfProtectedServiceServlet's javadoc it's an experimental servlet not advised to use in production code:

EXPERIMENTAL and subject to change. Do not use this in production code.