code: public static View resolveView(HttpServletRequest request, String viewName, String controllerName, ViewResolver viewResolver) throws Exception {
          GrailsWebRequest webRequest = GrailsWebRequest.lookup(request);
          Locale locale = webRequest != null ? webRequest.getLocale() : Locale.getDefault() ;
          return viewResolver.resolveViewName(addViewPrefix(viewName, controllerName), locale);
      }
docs: Resolves a view for the given view name and controller name
  @param request The request
  @param viewName The view name
  @param controllerName The controller name
  @param viewResolver The resolver
  @return A View or null
  @throws Exception Thrown if an error occurs