Implementation of ViewResolver that resolves a view based on the request file name
or Accept header.
The ContentNegotiatingViewResolver does not resolve views itself, but delegates to
other ViewResolvers. By default, these other view resolvers are picked up automatically
from the application context, though they can also be set explicitly by using the
viewResolvers property. Note that in order for this
view resolver to work properly, the order property needs to be set to a higher
precedence than the others (the default is Ordered.HIGHEST_PRECEDENCE).
This view resolver uses the requested media type to select a suitable
View for a request. The requested media type is determined through the configured
ContentNegotiationManager. Once the requested media type has been determined, this resolver
queries each delegate view resolver for a View and determines if the requested media type
is compatible with the view's
content type). The most compatible view is returned.
Additionally, this view resolver exposes the defaultViews property,
allowing you to override the views provided by the view resolvers. Note that these default views are
offered as candidates, and still need have the content type requested (via file extension, parameter,
or Accept header, described above).
For example, if the request path is /view.php, this view resolver will look for a view
that has the text/html content type (based on the html file extension). A request
for /view with a text/html request Accept header has the same result.
public void setUseNotAcceptableStatusCode(boolean useNotAcceptableStatusCode)
Indicate whether a 406 Not Acceptable
status code should be returned if no suitable view can be found.
Default is false, meaning that this view resolver returns null for
resolveViewName(String, Locale) when an acceptable view cannot be found.
This will allow for view resolvers chaining. When this property is set to true,
resolveViewName(String, Locale) will respond with a view that sets the
response status to 406 Not Acceptable instead.
public boolean isUseNotAcceptableStatusCode()
Whether to return HTTP Status 406 if no suitable is found.
public void setDefaultViews(java.util.List<View> defaultViews)
Set the default views to use when a more specific view can not be obtained
from the ViewResolver chain.
Note: To allow for ViewResolver chaining, a ViewResolver should
return null if a view with the given name is not defined in it.
However, this is not required: Some ViewResolvers will always attempt
to build View objects with the given name, unable to return null
(rather throwing an exception when View creation failed).