ApplicationHttpRequest cannot be cast to MultipartHttpServletRequest

springMVC 文件上傳轉換出錯解決：

MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest)request；

這一句會報錯：ApplicationHttpRequest cannot be cast to MultipartHttpServletRequest

那就通過這種方式：

MultipartResolver resolver = new CommonsMultipartResolver(request.getSession().getServletContext());
MultipartHttpServletRequest multipartRequest = resolver.resolveMultipart(request);

參考：http://www.cnblogs.com/cuyt/archive/2012/11/09/2763207.html