struts 2 action class instance variable initialization

Question

I am currently working a existing project.It's using Struts 2 + Spring 2.5.

There is one action class, let's call it ActionA.java, inside which, there is a instance variable which is a service interface, like,

class ActionA{

//variables

protected ServiceAInterface serviceA;

//action methods, utilizing serviceA methods

}

in spring bean definitions, there is a definition, as <bean id="serviceA" class="com.company.serviceAImplementationClass"/>

I didn't find anywhere else related to initialization of the serviceA variable, and really wondering, which part finds out the correct implementation class for this variable, and initialize it?

It really puzzle me. Thanks for any enlightenment.

Jackie

Answer 1

One way is to define service bean as

<bean id="serviceA" class="com.company.serviceAImplementationClass"/>

<bean id="actionClassA" class="com.company.ActionA">
   <property name="serviceA" ref="serviceA"/>
</bean>

and then in your class, write setter and getter for your service class.

class ActionA{

//variables

protected ServiceAInterface serviceA;

//action methods, utilizing serviceA methods

public ServiceAInterface getServiceA() {
   return this.serviceA;
}

public void setServiceA(ServiceAInterface serviceA)
   this.serviceA = serviceA;
}

}

Thats it. Service class bean will be initilized by spring during application start up and its reference will be assigned to your action class.