Spring HibernateDaoSupport创建多个会话

Question

I am using Struts2.3 + Spring 3.2.6 + Hibernate 3.X for my web application.

I am using annotations to manage the transaction. My DAO class is as below.

@Transactional(readOnly = true, rollbackFor={Exception.class})
public class CustomerDAOImpl extends HibernateDaoSupport implements CustomerDAO{

    //adds the customer
    @Transactional(propagation=Propagation.REQUIRED, rollbackFor = {Exception.class})
    public void addCustomer(Customer customer){
        Session session = getSession();
        System.out.println("M1() Hash Code: --->"+session.hashCode()+ " Thread id: "+Thread.currentThread().getId());
        //session.save(customer);
    }

    //return all the customers in list
    // @Transactional(propagation=Propagation.REQUIRED, rollbackFor = {Exception.class})
    @Transactional(readOnly = true)
    public List<Customer> listCustomer(){
        Session session = getSession();
        System.out.println("M2() Hash Code: --->"+session.hashCode()+ " Thread id: "+Thread.currentThread().getId());
        return null; //logic to get the list based on condition

    }

These methods will be called from service layer and it is like below;

customerDAO.addCustomer(customer);
customerDAO.listCustomer();

I am getting different sessions for same thread when the above code is executed.

Output:

M1() Hash Code: --->5026724 Thread id: 21
M2() Hash Code: --->8899550 Thread id: 21

Due to this, if any exception comes in method2() the data which is persisted using method1() is not rollback .

Please let me know, how to get the single session based on thread (if i go for my own HibernateFactory i lose transaction management by Spring) with out loosing spring transaction management.

Answer 1

If you are using Hibernate make your DAO class to extend HibernateDaoSupport. Now you can get session from getHibernateTemplate() method. That way you can have the session managed by spring-hibernate

You can try this -

appContext.xml

<tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
         <tx:method name="submit*" propagation="REQUIRED" read-only="false" rollback-for="Exception"/>
</tx:attributes>
    </tx:advice>
    <aop:config>
        <aop:pointcut id="appControllerTransactionPointCuts"
            expression="execution(* com.test.customer.bo.Custom.*(..))" />
<aop:advisor advice-ref="txAdvice" pointcut-ref="appControllerTransactionPointCuts" />
    </aop:config>

Remove -

<tx:annotation-driven transaction-manager="transactionManager" />

from appcontext.xml

Now AOP should manage transactions.

How Transactions work - Suppose you are persisting objects in multiple DAO methods and you want them all to happen in one transaction, then you have to apply transaction at the service layer method where the DAO methods are getting called. For e., in my case the service layer is com.test.customer.bo.Custom.*

If you are not doing so, then each of your DAO method will be executed in a separate transaction and will get persisted to database if no exception occurs. If exception occur in method2() of DAO layer it will not rollback method1() as it is already committed.