Sharing an HttpSession between JSP and EJB

Q

Is it possible to share an HttpSession between a JSP and EJB? What happens when I change a value in the HttpSession from inside an EJB?

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A

You can pass the HttpSession as parameter to an EJB method, only if all objects in session are serializable. This has to be consider as "passed-by-value", that means that it's read-only in the EJB.

If anything is altered from inside the EJB, it won't be reflected back to the HttpSession of the Servlet Container. The "pass-byreference" can be used between EJBs Remote Interfaces, as they are remote references.

While it IS possible to pass an HttpSession as a parameter to an EJB object, it is considered to be "bad practice" in terms of object oriented design. This is because you are creating an unnecessary coupling between back-end objects (ejbs) and front-end objects (HttpSession). Create a higher-level of abstraction for your ejb's api. Rather than passing the whole, fat, HttpSession (which carries with it a bunch of http semantics), create a class that acts as a value object (or structure) that holds all the data you need to pass back and forth between front-end/back-end.

Consider the case where your ejb needs to support a non-http-based client. This higher level of abstraction will be flexible enough to support it.

2007-04-03, 4956👍, 0💬