How to get beans defined in main-servlet.xml from controller

Question

I understand beans in my main-servlet.xml is in child context. And based on research I know I can get root ApplicationContext within my GreetingController through WebApplicationContextUtils. Which I'll get null because i didn't define such a root context in web.xml.

Now my question is how can i get child context and do something like childContext.getBean("forfun") without @AutoWired annotation,I think I've tested it and it works;

Thanks in advance for your reading and info.

Edit: AutoWire the ApplicationContext or implement ApplicationContextAware will help you get both the child and root ApplicationContext.

Edit2:I found another way to get the context created by defaultdispacher, the context is actually stored in servletcontext attributes with name org.springframework.web.servlet.FrameworkServlet.CONTEXT.(servletName) supposed your default servlet is main, you can get the context craete by defaultdispacher[main-servlet.xml] with the following code.

ApplicationContext context1=(WebApplicationContext) request.getSession().getServletContext().getAttribute("org.springframework.web.servlet.FrameworkServlet.CONTEXT.main")

But still don't understand why in the WebApplicationContextUtils method we can't access child context.

web.xml file

<webapp>
<servlet>
<servlet-name>main</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/main-servlet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>main</servlet-name>
<url-pattern>/main/*</url-pattern>
</servlet-mapping>
</web-app>

main-servlet.xml

<beans>
<bean name ="/testing/*" class="springmvc.GreetingController"></bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/Jsp/"
p:suffix=".jsp"/>
<bean id="forfun" class="springmvc.Foo"></bean>
</beans>

GreetingController.java

@Controller
public class GreetingController {

@AutoWired
Foo forfun;//this works even if forfun is defined in main-servlet.xml

@RequestMapping("/testing")
public String testing(HttpServletRequest request){
    ApplicationContext context = 
                WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
        Foo f=(Foo) context.getBean("forfun");//supposed to work if i have it defined in root context
    /*
    I would something like this
    ChildContext child = Utils.getChildContext(request);
    Foo f=(Foo) child.getBean("forfun");
    */
        return "test";
    }
}

Why do you want to get it through the WebApplicationContext? — Sotirios Delimanolis
Not for practical reason, just try to see if there's a way around. — Jing

Sotirios Delimanolis Sotirios Delimanolis · Accepted Answer · 2014-10-02T15:50:26

The main-servlet.xml you've declared above is loaded by your DispatcherServlet.

You can inject the corresponding WebApplicationContext with

@Autowired
private WebApplicationContext context;

and use it to get any bean defined in that context or a parent.

Note that this will work only if the bean you're injecting it into is created within the WebApplicationContext created by the DispatcherServlet.

Alternatively, as stated in the comments by M. Deinum, there's a static utility class called RequestContextUtils that provides a getWebApplicationContext(ServletRequest) method for doing the same thing.

How to get beans defined in main-servlet.xml from controller

1 Answers