如何从Servlets访问@ViewScoped托管bean？

Question

I would like to access a view scope managed bean inside a Servlet.

I searched for similar question and got these ones:

how to get beans from view scope which uses FacesContext.getCurrentInstance() , inapplicable inside a Servlet because it should give a null result

JSF - get managed bean by name which treats all other scopes but not viewscope

I'm going to think it is not possible, is it ?

There is the simple solution to change that bean scope to session scope but it is a last chance because I'm worried by memory consumption.

My final need is the following: the managebean contains some data displayed in a dataTable. The same page should include the image (mandatory) of chart representation of those data. The image can be produced by a Servlet but it needs to access the data or reload them from the db.

I also tried the <p:graphicImage> from PrimeFaces 2.X but it is not compatible with viewscope beans. Any suggestion?

Answer 1

That's not possible, no. The view scope is tied to a specific JSF view, which is no means of in a plain HTTP servlet request. Note that you can't access concrete request scoped beans during a plain HTTP servlet request either, they would always return null .

The session scope is the best what you can get. You can just remove the attribute from the session scope once you're finished with it in the servlet.

session.removeAttribute("somename");