CODEWITHSUNDEEP
springspring-mvc
Joly
Joly

Reputation: 3276

Best practice for using @SessionAttributes

I am trying to share data between two controllers in a Spring mvc application.

In Controller A I have annotated the class with @SessionAttributes({"mymodel1"}) and in the method which receives the first GET request I add it to the ModelMap: 

model.addAttribute("mymodel1", MyModel1);

I now want to read myModel1 from Controller B. In this Controller I have the following method which intercepts the POST requests and already has a different model in its parameters:

public String processSubmit(@ModelAttribute("mymodel2") MyModel2 mymodel2, BindingResult result, SessionStatus status, HttpServletRequest httpRequest)

Up to this point everything works fine and I am able to read mymodel2 from processSubmit however if I now want to add another @ModelAttribute("mymodel1") MyModel1 mymodel1 to this method signature I would have expected to be able to read the value I was setting in Controller A however I'm getting exceptions that the first model is no longer recognised.

So my question is: how can I read mymodel2 from Controller B?

Upvotes: 0

Views: 2035

Answers (2)

Rossen Stoyanchev
Rossen Stoyanchev

Reputation: 5008

The javadoc excerpt above is the most typical way @SessionAttributes is used. However, what Joly is describing should also work. Session attributes are stored via DefaultSessionAttributeStore, which by default does not prefix attribute names when it stores them in the session. That means if ControllerA and ControllerB both list an attribute called "mymodel1", they're actually referring to the same session attribute. You'll need to provide a little more information on the error you're getting and the actual controller code.

Upvotes: 1

Eugene
Eugene

Reputation: 120848

You can't do that with @SessionAttributes :

Session attributes as indicated using this annotation correspond to a specific handlers 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 handlers conversation.

For example I use this annotation when I want to validate elements with Hibernate validation, and after I submit the page and SOME elements are invalid I want the rest to be still on the page, but this is not your case. I think that the only way to do it would be with:

HttpSession.getAttribute()

Upvotes: 1

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