Question

Is there any way under spring 3.0 to access the HttpSession without including it in the method signature? What I really want to do is be able to pass in values from an HttpSession that CAN BE null.

Something like this:

@RequestMapping("/myHomePage")
public ModelAndView show(UserSecurityContext ctx) {}

instead of this:

@RequestMapping("/myHomePage")
public ModelAndView show(HttpSession session) {
      UserSecurityContext ctx = (UserSecurityContext) session.getAttribute("userSecurityCtx");
}

Answer 1

The @SessionAttribute annotation mentioned by @uthark is not suitable for this task – I thought it was too, but a bit of reading shows otherwise:

Session attributes as indicated using
this annotation correspond to a
specific handler’s model attributes,
getting transparently stored in a
conversational session. Those
attributes will be removed once the
handler indicates completion of its
conversational session. Therefore, use
this facility for such conversational
attributes which are supposed to be
stored in the session temporarily
during the course of a specific
handler’s conversation.

For permanent session attributes, e.g.
a user authentication object, use the
traditional session.setAttribute
method instead. Alternatively,
consider using the attribute
management capabilities of the generic
WebRequest interface.

In other words, @SessionAttribute is for storing conversation MVC-model objects in the session (as opposed to storing them as request attributes). It’s not intended for using with arbitrary session attributes. As you discovered, it only works if the session attribute is always there.

I’m not aware of any other alternative, I think you’re stuck with HttpSession.getAttribute()