org.springframework.web.portlet

Class DispatcherPortlet

java.lang.Object

javax.portlet.GenericPortlet

org.springframework.web.portlet.GenericPortletBean

org.springframework.web.portlet.FrameworkPortlet

org.springframework.web.portlet.DispatcherPortlet

All Implemented Interfaces:

java.util.EventListener, EventPortlet, Portlet, PortletConfig, ResourceServingPortlet, Aware, ApplicationListener<ContextRefreshedEvent>, EnvironmentAware, EnvironmentCapable

public class DispatcherPortlet
extends FrameworkPortlet

Central dispatcher for use within the Portlet MVC framework, e.g. for web UI controllers. Dispatches to registered handlers for processing a portlet request.

This portlet is very flexible: It can be used with just about any workflow, with the installation of the appropriate adapter classes. It offers the following functionality that distinguishes it from other request-driven Portlet MVC frameworks:

• It is based around a JavaBeans configuration mechanism.
• It can use any HandlerMapping implementation - pre-built or provided as part of an application - to control the routing of requests to handler objects. Default is a DefaultAnnotationHandlerMapping. HandlerMapping objects can be defined as beans in the portlet's application context, implementing the HandlerMapping interface, overriding the default HandlerMapping if present. HandlerMappings can be given any bean name (they are tested by type).
• It can use any HandlerAdapter; this allows for using any handler interface. The default adapter is SimpleControllerHandlerAdapter for Spring's Controller interface. A default AnnotationMethodHandlerAdapter will be registered as well. HandlerAdapter objects can be added as beans in the application context, overriding the default HandlerAdapter. Like HandlerMappings, HandlerAdapters can be given any bean name (they are tested by type).
• The dispatcher's exception resolution strategy can be specified via a HandlerExceptionResolver, for example mapping certain exceptions to error pages. Default is none. Additional HandlerExceptionResolvers can be added through the application context. HandlerExceptionResolver can be given any bean name (they are tested by type).
• Its view resolution strategy can be specified via a ViewResolver implementation, resolving symbolic view names into View objects. Default is InternalResourceViewResolver. ViewResolver objects can be added as beans in the application context, overriding the default ViewResolver. ViewResolvers can be given any bean name (they are tested by type).
• The dispatcher's strategy for resolving multipart requests is determined by a PortletMultipartResolver implementation. An implementations for Apache Commons FileUpload is included: CommonsPortletMultipartResolver. The MultipartResolver bean name is "portletMultipartResolver"; default is none.

NOTE: The @RequestMapping annotation will only be processed if a corresponding HandlerMapping (for type-level annotations) and/or HandlerAdapter (for method-level annotations) is present in the dispatcher. This is the case by default. However, if you are defining custom HandlerMappings or HandlerAdapters, then you need to make sure that a corresponding custom DefaultAnnotationHandlerMapping and/or AnnotationMethodHandlerAdapter is defined as well - provided that you intend to use @RequestMapping.

A web application can define any number of DispatcherPortlets. Each portlet will operate in its own namespace, loading its own application context with mappings, handlers, etc. Only the root application context as loaded by ContextLoaderListener, if any, will be shared.

Thanks to Rainer Schmitz, Nick Lothian and Eric Dalquist for their suggestions!

Since:

2.0

Author:

William G. Thompson, Jr., John A. Lewis, Juergen Hoeller

See Also:

Controller, ViewRendererServlet, ContextLoaderListener

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ACTION_EXCEPTION_RENDER_PARAMETER This render parameter is used to indicate forward to the render phase that an exception occurred during the action phase.
static java.lang.String	ACTION_EXCEPTION_SESSION_ATTRIBUTE Unlike the Servlet version of this class, we have to deal with the two-phase nature of the portlet request.
static java.lang.String	DEFAULT_VIEW_RENDERER_URL Default URL to ViewRendererServlet.
static java.lang.String	HANDLER_ADAPTER_BEAN_NAME Well-known name for the HandlerAdapter object in the bean factory for this namespace.
static java.lang.String	HANDLER_EXCEPTION_RESOLVER_BEAN_NAME Well-known name for the HandlerExceptionResolver object in the bean factory for this namespace.
static java.lang.String	HANDLER_MAPPING_BEAN_NAME Well-known name for the HandlerMapping object in the bean factory for this namespace.
static java.lang.String	MULTIPART_RESOLVER_BEAN_NAME Well-known name for the PortletMultipartResolver object in the bean factory for this namespace.
static java.lang.String	PAGE_NOT_FOUND_LOG_CATEGORY Log category to use when no mapped handler is found for a request.
protected static Log	pageNotFoundLogger Additional logger to use when no mapped handler is found for a request.
static java.lang.String	VIEW_RESOLVER_BEAN_NAME Well-known name for the ViewResolver object in the bean factory for this namespace.

Fields inherited from class org.springframework.web.portlet.FrameworkPortlet

DEFAULT_CONTEXT_CLASS, DEFAULT_NAMESPACE_SUFFIX, DEFAULT_USERINFO_ATTRIBUTE_NAMES, PORTLET_CONTEXT_PREFIX

Fields inherited from class org.springframework.web.portlet.GenericPortletBean

logger

Constructor Summary

Constructors

Constructor and Description
DispatcherPortlet()

Method Summary

Modifier and Type	Method and Description
protected ActionRequest	checkMultipart(ActionRequest request) Convert the request into a multipart request, and make multipart resolver available.
protected java.lang.Object	createDefaultStrategy(ApplicationContext context, java.lang.Class<?> clazz) Create a default strategy.
protected void	doActionService(ActionRequest request, ActionResponse response) Processes the actual dispatching to the handler for action requests.
protected void	doDispatch(PortletRequestDispatcher dispatcher, PortletRequest request, MimeResponse response) Perform a dispatch on the given PortletRequestDispatcher.
protected void	doEventService(EventRequest request, EventResponse response) Processes the actual dispatching to the handler for event requests.
protected void	doRender(View view, java.util.Map<java.lang.String,?> model, PortletRequest request, MimeResponse response) Actually render the given view.
protected void	doRenderService(RenderRequest request, RenderResponse response) Processes the actual dispatching to the handler for render requests.
protected void	doResourceService(ResourceRequest request, ResourceResponse response) Processes the actual dispatching to the handler for resource requests.
protected void	exposeActionException(PortletRequest request, StateAwareResponse response, java.lang.Exception ex) Expose the given action exception to the given response.
protected <T> java.util.List<T>	getDefaultStrategies(ApplicationContext context, java.lang.Class<T> strategyInterface) Create a List of default strategy objects for the given strategy interface.
protected <T> T	getDefaultStrategy(ApplicationContext context, java.lang.Class<T> strategyInterface) Return the default strategy object for the given strategy interface.
protected HandlerExecutionChain	getHandler(PortletRequest request) Return the HandlerExecutionChain for this request.
protected HandlerAdapter	getHandlerAdapter(java.lang.Object handler) Return the HandlerAdapter for this handler object.
PortletMultipartResolver	getMultipartResolver() Obtain this portlet's PortletMultipartResolver, if any.
protected void	initStrategies(ApplicationContext context) Refresh the strategy objects that this portlet uses.
protected void	noHandlerFound(PortletRequest request, PortletResponse response) No handler found -> throw appropriate exception.
void	onRefresh(ApplicationContext context) This implementation calls initStrategies(org.springframework.context.ApplicationContext).
protected ModelAndView	processHandlerException(RenderRequest request, RenderResponse response, java.lang.Object handler, java.lang.Exception ex) Determine an error ModelAndView via the registered HandlerExceptionResolvers.
protected ModelAndView	processHandlerException(ResourceRequest request, ResourceResponse response, java.lang.Object handler, java.lang.Exception ex) Determine an error ModelAndView via the registered HandlerExceptionResolvers.
protected void	render(ModelAndView mv, PortletRequest request, MimeResponse response) Render the given ModelAndView.
protected View	resolveViewName(java.lang.String viewName, java.util.Map<java.lang.String,?> model, PortletRequest request) Resolve the given view name into a View object (to be rendered).
void	setDetectAllHandlerAdapters(boolean detectAllHandlerAdapters) Set whether to detect all HandlerAdapter beans in this portlet's context.
void	setDetectAllHandlerExceptionResolvers(boolean detectAllHandlerExceptionResolvers) Set whether to detect all HandlerExceptionResolver beans in this portlet's context.
void	setDetectAllHandlerMappings(boolean detectAllHandlerMappings) Set whether to detect all HandlerMapping beans in this portlet's context.
void	setDetectAllViewResolvers(boolean detectAllViewResolvers) Set whether to detect all ViewResolver beans in this portlet's context.
void	setForwardActionException(boolean forwardActionException) Set whether to forward exceptions thrown during the action phase to the render phase via a session attribute.
void	setForwardEventException(boolean forwardEventException) Set whether to forward exceptions thrown during the event phase to the render phase via a session attribute.
void	setViewRendererUrl(java.lang.String viewRendererUrl) Set the URL to the ViewRendererServlet.

Methods inherited from class org.springframework.web.portlet.FrameworkPortlet

buildLocaleContext, createPortletApplicationContext, destroy, doDispatch, getContextClass, getContextConfigLocation, getNamespace, getPortletApplicationContext, getPortletContextAttributeName, getTitle, getUsernameForRequest, initFrameworkPortlet, initPortletApplicationContext, initPortletBean, onApplicationEvent, postProcessPortletApplicationContext, processAction, processEvent, processRequest, refresh, serveResource, setContextClass, setContextConfigLocation, setNamespace, setPublishContext, setPublishEvents, setThreadContextInheritable, setUserinfoUsernameAttributes

Methods inherited from class org.springframework.web.portlet.GenericPortletBean

addRequiredProperty, createEnvironment, getEnvironment, getPortletContext, getPortletName, init, initBeanWrapper, setEnvironment

Methods inherited from class javax.portlet.GenericPortlet

doEdit, doHeaders, doHelp, doView, getContainerRuntimeOptions, getDefaultNamespace, getInitParameter, getInitParameterNames, getNextPossiblePortletModes, getPortletConfig, getProcessingEventQNames, getPublicRenderParameterNames, getPublishingEventQNames, getResourceBundle, getSupportedLocales, init, render

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MULTIPART_RESOLVER_BEAN_NAME

public static final java.lang.String MULTIPART_RESOLVER_BEAN_NAME

Well-known name for the PortletMultipartResolver object in the bean factory for this namespace.

See Also:

Constant Field Values

HANDLER_MAPPING_BEAN_NAME

public static final java.lang.String HANDLER_MAPPING_BEAN_NAME

Well-known name for the HandlerMapping object in the bean factory for this namespace. Only used when "detectAllHandlerMappings" is turned off.

See Also:

setDetectAllViewResolvers(boolean), Constant Field Values

HANDLER_ADAPTER_BEAN_NAME

public static final java.lang.String HANDLER_ADAPTER_BEAN_NAME

Well-known name for the HandlerAdapter object in the bean factory for this namespace. Only used when "detectAllHandlerAdapters" is turned off.

See Also:

setDetectAllHandlerAdapters(boolean), Constant Field Values

HANDLER_EXCEPTION_RESOLVER_BEAN_NAME

public static final java.lang.String HANDLER_EXCEPTION_RESOLVER_BEAN_NAME

Well-known name for the HandlerExceptionResolver object in the bean factory for this namespace. Only used when "detectAllHandlerExceptionResolvers" is turned off.

See Also:

setDetectAllViewResolvers(boolean), Constant Field Values

VIEW_RESOLVER_BEAN_NAME

public static final java.lang.String VIEW_RESOLVER_BEAN_NAME

Well-known name for the ViewResolver object in the bean factory for this namespace.

See Also:

Constant Field Values

DEFAULT_VIEW_RENDERER_URL

public static final java.lang.String DEFAULT_VIEW_RENDERER_URL

Default URL to ViewRendererServlet. This bridge servlet is used to convert portlet render requests to servlet requests in order to leverage the view support in the org.springframework.web.view package.

See Also:

Constant Field Values

ACTION_EXCEPTION_SESSION_ATTRIBUTE

public static final java.lang.String ACTION_EXCEPTION_SESSION_ATTRIBUTE

Unlike the Servlet version of this class, we have to deal with the two-phase nature of the portlet request. To do this, we need to pass forward any exception that occurs during the action phase, so that it can be displayed in the render phase. The only direct way to pass things forward and preserve them for each render request is through render parameters, but these are limited to String objects and we need to pass the Exception itself. The only other way to do this is in the session. The bad thing about using the session is that we have no way of knowing when we are done re-rendering the request and so we don't know when we can remove the objects from the session. So we will end up polluting the session with an old exception when we finally leave the render phase of one request and move on to something else.

ACTION_EXCEPTION_RENDER_PARAMETER

public static final java.lang.String ACTION_EXCEPTION_RENDER_PARAMETER

This render parameter is used to indicate forward to the render phase that an exception occurred during the action phase.

See Also:

Constant Field Values

PAGE_NOT_FOUND_LOG_CATEGORY

public static final java.lang.String PAGE_NOT_FOUND_LOG_CATEGORY

Log category to use when no mapped handler is found for a request.

See Also:

Constant Field Values

pageNotFoundLogger

protected static final Log pageNotFoundLogger

Additional logger to use when no mapped handler is found for a request.

Constructor Detail

DispatcherPortlet

public DispatcherPortlet()

Method Detail

setDetectAllHandlerMappings

public void setDetectAllHandlerMappings(boolean detectAllHandlerMappings)

Set whether to detect all HandlerMapping beans in this portlet's context. Else, just a single bean with name "handlerMapping" will be expected.

Default is true. Turn this off if you want this portlet to use a single HandlerMapping, despite multiple HandlerMapping beans being defined in the context.

setDetectAllHandlerAdapters

public void setDetectAllHandlerAdapters(boolean detectAllHandlerAdapters)

Set whether to detect all HandlerAdapter beans in this portlet's context. Else, just a single bean with name "handlerAdapter" will be expected.

Default is "true". Turn this off if you want this portlet to use a single HandlerAdapter, despite multiple HandlerAdapter beans being defined in the context.

setDetectAllHandlerExceptionResolvers

public void setDetectAllHandlerExceptionResolvers(boolean detectAllHandlerExceptionResolvers)

Set whether to detect all HandlerExceptionResolver beans in this portlet's context. Else, just a single bean with name "handlerExceptionResolver" will be expected.

Default is true. Turn this off if you want this portlet to use a single HandlerExceptionResolver, despite multiple HandlerExceptionResolver beans being defined in the context.

setDetectAllViewResolvers

public void setDetectAllViewResolvers(boolean detectAllViewResolvers)

Set whether to detect all ViewResolver beans in this portlet's context. Else, just a single bean with name "viewResolver" will be expected.

Default is true. Turn this off if you want this portlet to use a single ViewResolver, despite multiple ViewResolver beans being defined in the context.

setForwardActionException

public void setForwardActionException(boolean forwardActionException)

Set whether to forward exceptions thrown during the action phase to the render phase via a session attribute.

Default is true. Turn this off if you want the portlet container to provide immediate exception handling for action requests.

See Also:

exposeActionException(javax.portlet.PortletRequest, javax.portlet.StateAwareResponse, Exception)

setForwardEventException

public void setForwardEventException(boolean forwardEventException)

Set whether to forward exceptions thrown during the event phase to the render phase via a session attribute.

Default is false. Turn this on if you want the DispatcherPortlet to forward the exception to the render phase, similar to what it does for action exceptions by default.

setViewRendererUrl

public void setViewRendererUrl(java.lang.String viewRendererUrl)

Set the URL to the ViewRendererServlet. That servlet is used to ultimately render all views in the portlet application.

onRefresh

public void onRefresh(ApplicationContext context)

This implementation calls initStrategies(org.springframework.context.ApplicationContext).

Overrides:

onRefresh in class FrameworkPortlet

Parameters:

context - the current Portlet ApplicationContext

See Also:

FrameworkPortlet.refresh()

initStrategies

protected void initStrategies(ApplicationContext context)

Refresh the strategy objects that this portlet uses.

May be overridden in subclasses in order to initialize further strategy objects.

getDefaultStrategy

protected <T> T getDefaultStrategy(ApplicationContext context,
                                   java.lang.Class<T> strategyInterface)

Return the default strategy object for the given strategy interface.

The default implementation delegates to getDefaultStrategies(org.springframework.context.ApplicationContext, java.lang.Class<T>), expecting a single object in the list.

Parameters:

context - the current Portlet ApplicationContext

strategyInterface - the strategy interface

Returns:

the corresponding strategy object

See Also:

getDefaultStrategies(org.springframework.context.ApplicationContext, java.lang.Class<T>)

getDefaultStrategies

protected <T> java.util.List<T> getDefaultStrategies(ApplicationContext context,
                                                     java.lang.Class<T> strategyInterface)

Create a List of default strategy objects for the given strategy interface.

The default implementation uses the "DispatcherPortlet.properties" file (in the same package as the DispatcherPortlet class) to determine the class names. It instantiates the strategy objects and satisifies ApplicationContextAware if necessary.

Parameters:

context - the current Portlet ApplicationContext

strategyInterface - the strategy interface

Returns:

the List of corresponding strategy objects

createDefaultStrategy

protected java.lang.Object createDefaultStrategy(ApplicationContext context,
                                                 java.lang.Class<?> clazz)

Create a default strategy.

The default implementation uses AutowireCapableBeanFactory.createBean(java.lang.Class<T>).

Parameters:

context - the current Portlet ApplicationContext

clazz - the strategy implementation class to instantiate

Returns:

the fully configured strategy instance

See Also:

ApplicationContext.getAutowireCapableBeanFactory()

getMultipartResolver

public PortletMultipartResolver getMultipartResolver()

Obtain this portlet's PortletMultipartResolver, if any.

Returns:

the PortletMultipartResolver used by this portlet, or null if none (indicating that no multipart support is available)

doActionService

protected void doActionService(ActionRequest request,
                               ActionResponse response)
                        throws java.lang.Exception

Processes the actual dispatching to the handler for action requests.

The handler will be obtained by applying the portlet's HandlerMappings in order. The HandlerAdapter will be obtained by querying the portlet's installed HandlerAdapters to find the first that supports the handler class.

Specified by:

doActionService in class FrameworkPortlet

Parameters:

request - current portlet action request

response - current portlet Action response

Throws:

java.lang.Exception - in case of any kind of processing failure

See Also:

GenericPortlet.processAction(javax.portlet.ActionRequest, javax.portlet.ActionResponse)

doRenderService

protected void doRenderService(RenderRequest request,
                               RenderResponse response)
                        throws java.lang.Exception

Processes the actual dispatching to the handler for render requests.

The handler will be obtained by applying the portlet's HandlerMappings in order. The HandlerAdapter will be obtained by querying the portlet's installed HandlerAdapters to find the first that supports the handler class.

Specified by:

doRenderService in class FrameworkPortlet

Parameters:

request - current portlet render request

response - current portlet render response

Throws:

java.lang.Exception - in case of any kind of processing failure

See Also:

GenericPortlet.doDispatch(javax.portlet.RenderRequest, javax.portlet.RenderResponse)

doResourceService

protected void doResourceService(ResourceRequest request,
                                 ResourceResponse response)
                          throws java.lang.Exception

Processes the actual dispatching to the handler for resource requests.

The handler will be obtained by applying the portlet's HandlerMappings in order. The HandlerAdapter will be obtained by querying the portlet's installed HandlerAdapters to find the first that supports the handler class.

Specified by:

doResourceService in class FrameworkPortlet

Parameters:

request - current portlet render request

response - current portlet render response

Throws:

java.lang.Exception - in case of any kind of processing failure

See Also:

GenericPortlet.serveResource(javax.portlet.ResourceRequest, javax.portlet.ResourceResponse)

doEventService

protected void doEventService(EventRequest request,
                              EventResponse response)
                       throws java.lang.Exception

Processes the actual dispatching to the handler for event requests.

The handler will be obtained by applying the portlet's HandlerMappings in order. The HandlerAdapter will be obtained by querying the portlet's installed HandlerAdapters to find the first that supports the handler class.

Specified by:

doEventService in class FrameworkPortlet

Parameters:

request - current portlet action request

response - current portlet Action response

Throws:

java.lang.Exception - in case of any kind of processing failure

See Also:

GenericPortlet.processEvent(javax.portlet.EventRequest, javax.portlet.EventResponse)

checkMultipart

protected ActionRequest checkMultipart(ActionRequest request)
                                throws MultipartException

Convert the request into a multipart request, and make multipart resolver available. If no multipart resolver is set, simply use the existing request.

Parameters:

request - current HTTP request

Returns:

the processed request (multipart wrapper if necessary)

Throws:

MultipartException

getHandler

protected HandlerExecutionChain getHandler(PortletRequest request)
                                    throws java.lang.Exception

Return the HandlerExecutionChain for this request. Try all handler mappings in order.

Parameters:

request - current portlet request

Returns:

the HandlerExecutionChain, or null if no handler could be found

Throws:

java.lang.Exception

noHandlerFound

protected void noHandlerFound(PortletRequest request,
                              PortletResponse response)
                       throws java.lang.Exception

No handler found -> throw appropriate exception.

Parameters:

request - current portlet request

response - current portlet response

Throws:

java.lang.Exception - if preparing the response failed

getHandlerAdapter

protected HandlerAdapter getHandlerAdapter(java.lang.Object handler)
                                    throws PortletException

Return the HandlerAdapter for this handler object.

Parameters:

handler - the handler object to find an adapter for

Throws:

PortletException - if no HandlerAdapter can be found for the handler. This is a fatal error.

exposeActionException

protected void exposeActionException(PortletRequest request,
                                     StateAwareResponse response,
                                     java.lang.Exception ex)

Expose the given action exception to the given response.

Parameters:

request - current portlet request

response - current portlet response

ex - the action exception (may also come from an event phase)

render

protected void render(ModelAndView mv,
                      PortletRequest request,
                      MimeResponse response)
               throws java.lang.Exception

Render the given ModelAndView. This is the last stage in handling a request. It may involve resolving the view by name.

Parameters:

mv - the ModelAndView to render

request - current portlet render request

response - current portlet render response

Throws:

java.lang.Exception - if there's a problem rendering the view

resolveViewName

protected View resolveViewName(java.lang.String viewName,
                               java.util.Map<java.lang.String,?> model,
                               PortletRequest request)
                        throws java.lang.Exception

Resolve the given view name into a View object (to be rendered).

Default implementations asks all ViewResolvers of this dispatcher. Can be overridden for custom resolution strategies, potentially based on specific model attributes or request parameters.

Parameters:

viewName - the name of the view to resolve

model - the model to be passed to the view

request - current portlet render request

Returns:

the View object, or null if none found

Throws:

java.lang.Exception - if the view cannot be resolved (typically in case of problems creating an actual View object)

See Also:

ViewResolver.resolveViewName(java.lang.String, java.util.Locale)

doRender

protected void doRender(View view,
                        java.util.Map<java.lang.String,?> model,
                        PortletRequest request,
                        MimeResponse response)
                 throws java.lang.Exception

Actually render the given view.

The default implementation delegates to ViewRendererServlet.

Parameters:

view - the View to render

model - the associated model

request - current portlet render/resource request

response - current portlet render/resource response

Throws:

java.lang.Exception - if there's a problem rendering the view

doDispatch

protected void doDispatch(PortletRequestDispatcher dispatcher,
                          PortletRequest request,
                          MimeResponse response)
                   throws java.lang.Exception

Perform a dispatch on the given PortletRequestDispatcher.

The default implementation uses a forward for resource requests and an include for render requests.

Parameters:

dispatcher - the PortletRequestDispatcher to use

request - current portlet render/resource request

response - current portlet render/resource response

Throws:

java.lang.Exception - if there's a problem performing the dispatch

processHandlerException

protected ModelAndView processHandlerException(RenderRequest request,
                                               RenderResponse response,
                                               java.lang.Object handler,
                                               java.lang.Exception ex)
                                        throws java.lang.Exception

Determine an error ModelAndView via the registered HandlerExceptionResolvers.

Parameters:

request - current portlet request

response - current portlet response

handler - the executed handler, or null if none chosen at the time of the exception (for example, if multipart resolution failed)

ex - the exception that got thrown during handler execution

Returns:

a corresponding ModelAndView to forward to

Throws:

java.lang.Exception - if no error ModelAndView found

processHandlerException

protected ModelAndView processHandlerException(ResourceRequest request,
                                               ResourceResponse response,
                                               java.lang.Object handler,
                                               java.lang.Exception ex)
                                        throws java.lang.Exception

Determine an error ModelAndView via the registered HandlerExceptionResolvers.

Parameters:

request - current portlet request

response - current portlet response

handler - the executed handler, or null if none chosen at the time of the exception (for example, if multipart resolution failed)

ex - the exception that got thrown during handler execution

Returns:

a corresponding ModelAndView to forward to

Throws:

java.lang.Exception - if no error ModelAndView found