接口 PortletMultipartResolver

public interface PortletMultipartResolver

Portlet version of Spring's multipart resolution strategy for file uploads as defined in RFC 1867.

Implementations are typically usable both within any application context and standalone.

There is one concrete implementation included in Spring:

• CommonsMultipartResolver for Apache Commons FileUpload

There is no default resolver implementation used for Spring DispatcherPortlets, as an application might choose to parse its multipart requests itself. To define an implementation, create a bean with the id "portletMultipartResolver" in a DispatcherPortlet's application context. Such a resolver gets applied to all requests handled by that DispatcherPortlet.

If a DispatcherPortlet detects a multipart request, it will resolve it via the configured PortletMultipartResolver and pass on a wrapped Portlet ActionRequest. Controllers can then cast their given request to the MultipartActionRequest interface, being able to access MultipartFiles. Note that this cast is only supported in case of an actual multipart request.

 public void handleActionRequest(ActionRequest request, ActionResponse response) {
   MultipartActionRequest multipartRequest = (MultipartActionRequest) request;
   MultipartFile multipartFile = multipartRequest.getFile("image");
   ...
 }

Instead of direct access, command or form controllers can register a ByteArrayMultipartFileEditor or StringMultipartFileEditor with their data binder, to automatically apply multipart content to form bean properties.

Note: There is hardly ever a need to access the MultipartResolver itself from application code. It will simply do its work behind the scenes, making MultipartActionRequests available to controllers.