Spring HandlerMethodArgumentResolver not executing

Question

I am using Spring MVC 3.2.2

I have defined a custom HandlerMethodArgumentResolver class like this

public class CurrentUserArgumentResolver implements         


        

Answer 1

If anybody ever wants to prioritize custom handlers over default handlers added by spring, here's a snippet that does it for me, I do this in a @Configuration file

private @Inject RequestMappingHandlerAdapter adapter;

@PostConstruct
public void prioritizeCustomArgumentMethodHandlers () {
  List<HandlerMethodArgumentResolver> argumentResolvers = 
      new ArrayList<> (adapter.getArgumentResolvers ());
  List<HandlerMethodArgumentResolver> customResolvers = 
      adapter.getCustomArgumentResolvers ();
  argumentResolvers.removeAll (customResolvers);
  argumentResolvers.addAll (0, customResolvers);
  adapter.setArgumentResolvers (argumentResolvers);
}

Answer 2

OK I worked out that Spring was already resolving the Principal object in my above example and so my argument resolver was not kicking in. I had been lazy and added the @CurrentUser annotation to an existing parameter.

So I changed my example

@RequestMapping(method = RequestMethod.POST, value = "/update")
public ModelAndView update(@RequestParam MultipartFile background, @CurrentUser Principal principal) {
  ...
}

to use my User model class

@RequestMapping(method = RequestMethod.POST, value = "/update")
public ModelAndView update(@RequestParam MultipartFile background, @CurrentUser User user) {
  ...
}

and now it works!

Answer 3

I use the property customArgumentResolvers to load bean, like this:

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <property name="messageConverters">
            <list>
                <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                    <property name="supportedMediaTypes">
                        <list>
                            <value>text/html;charset=UTF-8</value>
                            <value>text/plain;charset=UTF-8</value>
                            <value>application/json;charset=UTF-8</value>
                        </list>
                    </property>
                </bean>
            </list>
        </property>
         <property name="customArgumentResolvers">
         <list>
             <bean id="MyTestMethodArgumentResolver" class="com.gst.authorization.resolvers.MyTestMethodArgumentResolver"></bean>           
             <bean id="currentUserMethodArgumentResolver" class="com.gst.authorization.resolvers.CurrentUserMethodArgumentResolver">
                            <property name="userModelClass" value="com.gst.model.appuser.AppUser" />
                    <property name="userModelRepository" ref="userRepository" />
                </bean>
         </list>         
         </property>
    </bean> 
    <mvc:annotation-driven />