What is a MultipartResolver and when its used?

Ref:- http://howtodoinjava.com/2015/03/02/spring-mvc-interview-questions-with-answers/

Spring comes with MultipartResolver to handle file upload in web application. There are two concrete implementations included in Spring:

1. CommonsMultipartResolver for Jakarta Commons FileUpload
2. StandardServletMultipartResolver for Servlet 3.0 Part API

To define an implementation, create a bean with the id “multipartResolver” in a DispatcherServlet’s application context. Such a resolver gets applied to all requests handled by that DispatcherServlet.

If a DispatcherServlet detects a multipart request, it will resolve it via the configured MultipartResolver and pass on a wrapped HttpServletRequest. Controllers can then cast their given request to the MultipartHttpServletRequest interface, which permits access to any MultipartFiles.