Spring & JTA

[Gavin Tranter]

Hi all,
Is my day for questions. I got landed with a web app project, and decided to use spring MVC.

I liked its "layered" approach so I could get teh app up and running and then worry about expaniding it out with things like Transactions, Security and perhaps using ORM.

However, if all I need to do in a single DB environment is:

<bean id="transactionManager"  class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>

If i am understanding this layered/modulor approach right, I shouldnt have to do too much to update my code to take advantage of another service (JTA in this case) but i have so far only seen the above entry in the jPetStore example, so I feel I am missing something, it cant be that easy.

G

[Valentin Tanase]

Hi,

I suppose that you'd like using declarative transactions (via AOP) with Spring. You may need then to read about the Spring transaction management here:

http://www.springframework.org/docs/reference/transaction.html

In a nutshell you need to define your transaction manager to be JTA compatible. If you�re using WAS it might look something like this:

    <bean id="wsJtaTm" class="org.springframework.transaction.jta.WebSphereTransactionManagerFactoryBean"/>
 
    <bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">
        <property name="transactionManager"><ref local="wsJtaTm"/></property>
    </bean>

For most of the app servers using only the JtaTransactionManager should be quite enough.

Now assuming you have a controller bean that uses a DAO (implemented using an ORM tool like Hibernate) that updates two different databases, which should happen within the same transaction:

    <bean id="removeTransactionController" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
        <property name="transactionManager" ref="transactionManager"/>
        <property name="target" ref="removeTransactionControllerTarget"/>
        <property name="transactionAttributes">
        <props>
            <prop key="*">PROPAGATION_REQUIRED</prop>
        </props>
        </property>
    </bean>
 
    <bean id="removeTransactionControllerTarget" class="com.viewer.web.action.impl.RemoveTransactionController">
        <property name="esbTransactionQuery">
            <ref bean="esbTransactionQuery" />
        </property>
</bean>

The trick here is that you�ll map the requests to a proxy bean ( removeTransactionController), which will actually do the transaction management for you (Spring uses the cglib api in order to build this proxy bean at runtime):

    <bean id="urlMapping"
        class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/removeTransactions.html">removeTransactionController</prop>
                �
            </props>
        </property>
    </bean>

If your app doesn�t use global transactions, then using the HibernateTransactionManager could be your best choice with spring-hibernate applications:

    <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory"><ref bean="sessionFactory"/></property>
    </bean>

Basically this is how it works.
Regards.

[Gavin Tranter]

Thanks for the detailed answer.

It sounds like I wont be needing JTA for my app then, as I only have one DB on one server to deal with.

G

[Valentin Tanase]

You're very welcome Gavin.