Using Spring with multiple databases Part 4

In your web config file (web.xml) you reference your applicationcontext.xml file and any other configuration file that you need to use.
To configure Atomikos we created a xml file called jndi.xml and reference it in our web.xml file like so:

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/applicationContext.xml,
/WEB-INF/jndi.xml
</param-value>
</context-param>

Here is how we configured Atomikos Transaction Manager in our jndi.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jee="http://www.springframework.org/schema/jee"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd">

<bean id="userTransactionService"
class="com.atomikos.icatch.config.UserTransactionServiceImp"
init-method="init" destroy-method="shutdownForce">
<constructor-arg>
<!-- IMPORTANT: specify all Atomikos properties here -->
<props>
<prop key="com.atomikos.icatch.service">
com.atomikos.icatch.standalone.UserTransactionServiceFactory
</prop>
<prop key="com.atomikos.icatch.enable_logging">
false
</prop>
</props>
</constructor-arg>
</bean>



<!--JTA Manager-->
<bean id="AtomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager"
init-method="init" destroy-method="close">

<!--
when close is called, should we force
transactions to terminate or not?
-->
<property name="forceShutdown" value="false" />
</bean>

<!--Also use Atomikos UserTransactionImp,
needed to configure Spring-->
<bean id="AtomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
<property name="transactionTimeout" value="300" />
</bean>

<bean id="jndi"
class="org.apache.xbean.spring.jndi.SpringInitialContextFactory"
factory-method="makeInitialContext">
<property name="entries">
<map>
<entry key="java:comp/TransactionManager" value-ref="AtomikosTransactionManager" />
<entry key="java:comp/UserTransaction" value-ref="AtomikosUserTransaction" />
<entry key="java:comp/UserTransactionService" value-ref="AtomikosUserTransaction" />
</map>
</property>
</bean>

</beans>

In the current trunk of Spring 3.0.0, when using the Spring MVC framework , I ended up having to place @Transactional (which tells the JVM to create a transaction) in my controller classes. I would have preferred to have them on my Data Access objects, but my Unit Tests revealed that Transactions only got created in the Spring MVC world when placed on my Controller classes.
Here is a code snippet example:

@Controller
@TransactionConfiguration(transactionManager="jtaTransactionManager", defaultRollback=false)
@Transactional
public class WizardController {

private static final Logger log = Logger
.getLogger(WizardController.class);

@Autowired
UserService userService;

In part 5, I will go over how to setup unit tests using JUnit 4 and Spring's Unit Test Annotations.