org.springframework.web.portlet.multipart

## Interface PortletMultipartResolver

All Known Implementing Classes:
  CommonsPortletMultipartResolver

    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 Jakarta 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 `MultipartResolver` 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 command 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.

Since:
  2.0
Author:
  Juergen Hoeller
See Also:
  `MultipartActionRequest`, `MultipartFile`, `CommonsPortletMultipartResolver`, `ByteArrayMultipartFileEditor`, `StringMultipartFileEditor`, `DispatcherPortlet`

### Method Summary

Methods
`void` `cleanupMultipart(MultipartActionRequest request)` Cleanup any resources used for the multipart handling, such as storage for any uploaded file(s).
`boolean` `isMultipart(ActionRequest request)` Determine if the given request contains multipart content.
`MultipartActionRequest` `resolveMultipart(ActionRequest request)` Parse the given portlet request into multipart files and parameters, and wrap the request inside a MultipartActionRequest object that provides access to file descriptors and makes contained parameters accessible via the standard PortletRequest methods.

### Method Detail

#### isMultipart

    boolean isMultipart(ActionRequest request)

Determine if the given request contains multipart content.

Will typically check for content type "`multipart/form-data`", but the actually accepted requests might depend on the capabilities of the resolver implementation.

Parameters:
  `request` - the portlet request to be evaluated
Returns:
  whether the request contains multipart content

#### resolveMultipart

    MultipartActionRequest resolveMultipart(ActionRequest request)
                                            throws MultipartException

Parse the given portlet request into multipart files and parameters, and wrap the request inside a MultipartActionRequest object that provides access to file descriptors and makes contained parameters accessible via the standard PortletRequest methods.

Parameters:
  `request` - the portlet request to wrap (must be of a multipart content type)
Returns:
  the wrapped portlet request
Throws:
  `MultipartException` - if the portlet request is not multipart, or if implementation-specific problems are encountered (such as exceeding file size limits)
See Also:
  `MultipartRequest.getFile(java.lang.String)`, `MultipartRequest.getFileNames()`, `MultipartRequest.getFileMap()`, `PortletRequest.getParameter(java.lang.String)`, `PortletRequest.getParameterNames()`, `PortletRequest.getParameterMap()`

#### cleanupMultipart

    void cleanupMultipart(MultipartActionRequest request)

Cleanup any resources used for the multipart handling, such as storage for any uploaded file(s).

Parameters:
  `request` - the request to cleanup resources for