I'm using Spring with JPA and Hibernate. I've got some DAO-Classes that are annotated with @Repositoy and some Controller-Classes. When I call one of the dao's methods in my controller to load some entities I get back the Entity and after that, I want to get some other entities that are stored in a field of the first loaded entity. But at that time spring has already closed the session and lazy loading is no longer possible.
My db.xml configuration:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/data/jpa
http://www.springframework.org/schema/data/jpa/spring-jpa.xsd" default-autowire="byName">
<!-- Scans within the base package of the application for @Components to configure as beans -->
<bean id="placeholderConfig"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:db.properties" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<!-- <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="jpaVendorAdapter" />
</bean> -->
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true" />
<property name="generateDdl" value="true" />
<property name="databasePlatform" value="${db.dialect}" />
</bean>
</property>
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${db.driver}" />
<property name="url" value="${db.url}" />
<property name="username" value="${db.username}" />
<property name="password" value="${db.password}" />
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" />
</beans>
The method in the Dao is annotated as follows:
@Transactional(readOnly = true, propagation=Propagation.REQUIRED)
now I wanna do something like this:
@Controller
public class HomeController{
@Autowired
private UserDao userDao;
@RequestMapping(value = "/", method = RequestMethod.GET)
public ResponseEntity<String> home(){
...
User user = userDao.findUser(id);
Set<Order> orders = user.getOrders();
...
String myResult = ...;
return jsonService.generateResponse(myResult);
}
}
@Repository
public class UserDao{
@PersistenceContext
private EntityManager entityManager;
public User findUser(Integer id){
return entityManager.find(User.class, id);
}
}
The set of orders should be lazy-loaded but i get the following exception: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role:...,no session or session was closed
root cause: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: ..., no session or session was closed
I tried to annotate the method in Controller wirt @Transactional and also to set mode="aspectj" in annotation-driven property in the db.xml, but nothing did work. Is there any way to lazy load the orders of the user?
For any help, thanking you in anticipation!
