@Target(value=PARAMETER) @Retention(value=RUNTIME) @Documented public @interface SessionAttribute
The main motivation is to provide convenient access to existing, permanent session attributes (e.g. user authentication object) with an optional/required check and a cast to the target method parameter type.
For use cases that require adding or removing session attributes consider
injecting org.springframework.web.context.request.WebRequest
or
javax.servlet.http.HttpSession
into the controller method.
For temporary storage of model attributes in the session as part of the
workflow for a controller, consider using SessionAttributes
instead.
RequestMapping
,
SessionAttributes
,
RequestAttribute
public abstract boolean required
Defaults to true
, leading to an exception being thrown
if the attribute is missing in the session or there is no session.
Switch this to false
if you prefer a null
or Java 8
java.util.Optional
if the attribute doesn't exist.