在Spring 3中通过注释注入与通过XML文件注入。与继承相关的限制

Question

I have the following abstract class, with a property called portletBaseViewName which is meant to be different for every concrete Controller extending AbstractController .

public abstract class AbstractController {

    private String portletBaseViewName;

    protected String getPortletBaseViewName() {
        return portletBaseViewName;
    }

    @Required
    @Value("")
    public void setPortletBaseViewName(String portletBaseViewName) {
        this.portletBaseViewName = portletBaseViewName;
    }

}

@Controller
@RequestMapping("VIEW")
public class ReservationOfBooksViewController extends AbstractController{}

I know that is possible declaring the injections in a XML, doing so:

<bean id="abstractController" class="es.alcampo.portalweb.portlets.common.controller.AbstractController" abstract="true">
    <property name="portletBaseViewName" value="" />
</bean>

<bean id="reservationOfBooksViewController" class="es.example.portalweb.portlets.reservationofbooks.controller.ReservationOfBooksViewController" parent="abstractController">
    <property name="portletBaseViewName" value="reservationOfBooks" />
</bean>

<bean id="myShopViewController" class="es.example.portalweb.portlets.reservationofbooks.controller.MyShopViewController" parent="abstractController">
    <property name="portletBaseViewName" value="myShop" />
</bean>

Do I need to redefine?:

@Controller
@RequestMapping("VIEW")
public class ReservationOfBooksViewController extends AbstractController{
    @Value("reservationOfBooks")
    public void setPortletBaseViewName(String portletBaseViewName) {
        super.setPortletBaseViewName(portletBaseViewName);
    }
}

I don't like the previous option, which would be the most elegant option if there is to reach the purpose of injecting one value or another depending on the concrete class through annotations?

I know inheritance and annotations sometimes conflict.

Thanks a lot.

Answer 1

Do you actually need @Value here?

@Value is useful when it contains some expressions evaluated by Spring at runtime. Otherwise you can replace it with explicit initialization (and keeping the setter method allows you to override this values from XML configuration):

public abstract class AbstractController { 
    protected String portletBaseViewName = "";      

    public void setPortletBaseViewName(String portletBaseViewName) { 
        this.portletBaseViewName = portletBaseViewName; 
    } 
} 

@Controller  
@RequestMapping("VIEW")  
public class ReservationOfBooksViewController extends AbstractController{  
    public ReservationOfBooksViewController() {
        this.portletBaseViewName = "reservationOfBooks";
    }
}

Answer 2

As shown by @axtavt in previous answer, you don't need any annotation in AbstractController . In addition, you don't need to define abstractController in XML. In case, you want to configure common properties in all of its subclasses, you can put them in abstract bean (without any class name):

<!-- define common properties in abstract bean-->
<bean id="controllerTemplate" abstract="true" />



<bean id="reservationOfBooksViewController" class="es.example.portalweb.portlets.reservationofbooks.controller.ReservationOfBooksViewController" parent="controllerTemplate">
<property name="portletBaseViewName" value="reservationOfBooks" />

In subclasses, @Value annotation is not required and you can use 'getPortletBaseViewName()' method to get view name.