Spring is an, among other things, an Inversion of Control framework. As of WebWork 2.2, it is the only supported IoC container. You can find out more about Spring at http://www.springframework.org.

Enabling Spring Integration

Turning on Spring support in WebWork is simply a matter of installing the latest Spring jars in to your classpath and then adding the following entry to webwork.properties:

webwork.objectFactory = spring

If you want to change from the default autowiring mode, which is to auto-wire by name (i.e. to look for beans defined in Spring with the same name as your bean property), then you'll also need a setting for this in your webwork.properties:

webwork.objectFactory.spring.autoWire = type

Options for this setting are:

At this point, all objects will at least try to get created by Spring. If they cannot be created by Spring, then WebWork will create the object itself. Next, you'll need to turn on the Spring listener in web.xml:

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!-- Context Configuration locations for Spring XML files -->
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext-*.xml</param-value>
</context-param>

Sample Spring Configuration

At this point, you can add the standard Spring configuration at WEB-INF/applicationContext.xml. An example of this configuration is:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans default-autowire="autodetect">
    <bean id="personManager" class="com.acme.PersonManager"/>
    ...
</beans>

Switching from Builtin IoC to Spring

Switching is quite easy. Spring setup is done as described above. To complete migration, you will have to

1. transfer your configured components from components.xml to applictationContext.xml appropriately. You can safely delete components.xml afterwards.
2. remove the Component Interceptor from your interceptor stack in xwork.xml. Although it does not hurt to leave it there, it is simply redundant from now on.

Initializing Actions from Spring

Normally, in xwork.xml you specify the class for each action. When using the SpringObjectFactory (configured as shown above), this means that WebWork will ask Spring to create the action and wire up dependencies as specified by the default auto-wire behavior. The SpringObjectFactory will also apply all bean post processors to do things like proxy your action for transactions, security, etc. which Spring can automatically determine without explicit configuration. For most usages, this should be all you need for configuring your actions to have services and dependencies applied.

However, sometimes you might want the bean to be completely managed by Spring. This is useful, for example, if you wish to apply more complex AOP or Spring-enabled technologies, such as Acegi, to your beans. To do this, all you have to do is configure the bean in your Spring applicationContext.xml and then change the class attribute from your WebWork action in the xwork.xml to use the bean name defined in Spring instead of the class name.

Your xwork.xml file would then have the action class attributes changed, leaving it like this:

<!DOCTYPE xwork PUBLIC "-//OpenSymphony Group//XWork 1.0//EN" "http://www.opensymphony.com/xwork/xwork-1.1.dtd">

<xwork>
    <include file="webwork-default.xml"/>

    <package name="default" extends="webwork-default">
        <action name="foo" class="com.acme.Foo">
            <result>foo.ftl</result>
        </action>
    </package>

    <package name="secure" namespace="/secure" extends="default">
        <action name="bar" class="bar">
            <result>bar.ftl</result>
        </action>
    </package>
</xwork>

Where you have a Spring bean defined in your applicationContext.xml named "bar". Note that the com.acme.Foo action did not need to be changed, because it can be autowired.

Remember: this is not required. This is only needed if you wish to override the default behavior when the action is created in WebWork by decorating it with Spring-enabled interceptors and IoC that cannot be automatically determined by Spring. Keep in mind that WebWork's Spring integration will do standard IoC, using whatever auto-wiring you specify, even if you don't explicitely map each action in Spring. So typically you don't need to do this, but it is good to know how this can be done if you need to.