In a Spring-mvc interceptor, how can I access to the handler controller method?

Question

In a Spring-mvc interceptor I want to access to the handler controller method

public class CustomInterceptor implements HandlerInterceptor  {
    public boolean preHandle(
        HttpServletRequest request,HttpServletResponse response, 
            Object handler) {

        log.info(handler.getClass().getName()); //access to the controller class
        //I want to have the controller method
        ...
        return true;
   }
   ...
}

I have found :

how-to-get-controller-method-name-in-spring-interceptor-prehandle-method

But it only work around. I want the method name to access to the annotation.

Answer 1

HandlerInterceptors will only provide you access to the HandlerMethod IF you have registered your interceptors like so :

@EnableWebMvc
@Configuration
public class InterceptorRegistry extends WebMvcConfigurerAdapter {

    @Override
    public void addInterceptors(org.springframework.web.servlet.config.annotation.InterceptorRegistry registry) {
        registry.addInterceptor(new InternalAccessInterceptor());
        registry.addInterceptor(new AuthorizationInterceptor());
    }

}

In all other cases, the handler object will point to the controller. Most documentation on the web seemed to have missed this subtle point.

Answer 2

You can cast the Object handler to HandlerMethod.

HandlerMethod method = (HandlerMethod) handler;

Note however that the handler argument passed to preHandle is not always a HandlerMethod (careful with ClassCastException). HandlerMethod then has methods you can use to get annotations, etc.