Retrieving lists from other layer into a JSP page - Design Question

Question

Hi all,
What should be a good design technique in order to allow a JSP page to present some list obtained from other layer of my application. I intend to leave only presentation logic in the JSP layer, while all data access will be in other layer.
For example, I have a JSP page that will show the results of a SQL query originated from an entry form in other JSP page. Let's name them 'search.jsp' and 'result.jsp'
I want that all JDBC access be done in some other layer.
Question 1:
What would be better for this task? A servlet or a bean? (A bean, I suppose?)
Then this bean (?) would have to find some way to pass all the result set into this 'result.jsp'. I think it would be very poor design if I used some Data Object, because it would have to store all rows and pass them at once.
I don't want, either, that the presentation (JSP) layer access directly the data access layer (JDBC, files...). This way, I don't want any JSP page accessing the Resultset object directly.
Question 2:
What do you think could be a good design technique?
I thought of some intermediate layer that provided data objects and data access interfaces. I mean, as my data will come from different sources, like some database (JDBC), some Electronic Document Manager, I thought of having a common access interface, that would provide methods for accessing the resultsets. This could be even a java.util.Enumeration that has a hasMoreElements() method that could be implemented as the next() method from JDBC result sets and the nextElement() method that would actually bring the next row of data.
This way the JSP layer would see only hasMoreElements() and nextElement() methods from the middle layer. On the other hand, the data layer would provide as many different implementations to this access interface (Enumeration?) as there were data sources (JDBC, Files, ...)
Question 3:
What do you think of this design?
Question 4:
Is there any flaw in my approach? Which?
Question 5:
Could you suggest other designs?
I really thank you all, for any kind of answer. I actually use this design for development, however I've never seriously discussed it with someone... this is going to be of great value for me.
Regards,
Filipe Fedalto

Answer 1

Well I saw you question and I'll tell you what I do.
I have JSP's which post form data to servlets.
The servlet then calls a factory to produce a ResultContainer (analagous to your lists) which is generated
via JDBC, and/or request parameters etc...
this provides a single point of reference and a "group" of containers (functions really) that can be produced and reused (same container different amount of data)
I also have other static classes which can manipulate the data in the containers
(such as add additional info to the items in the containers) before I forward the container (request attribute)
to the JSP page
Additionally I use Type safe constants for all my HTML form tag names (easier to change and ensure the same name is used everywhere when reading parameters) and again for item statuses
and any other info I need to send along with the page (using Javascript to update the
status to another type safe constant).
I've found that using factories for ResultContainers is very worthwhile and allows you to implement additional servlets extremely quickly (mostly reusing containers that exist) and since the
container is the same for all my JSPs (this may not be the case with you) I can implement JSP's
very quickly as well (just change the view)
btw I refrain from calling my ResultContainer a bean because it is not serializable
I don't know if this will help but at least it gives me a forum to test my ideas
Thanks