JSPs are much easier to work with in the presentation layer -- you can use
raw markup instead of enclosing all output in
response.getWriter.println("..."). Since you can include raw Java in JSPs as
well, you technically don't need servlets to build a full Java application.
That said, servlets are vital if you want to build an easy-to-maintain
application, reduce redundant code, and so forth.
In the Java Guestbook tutorial, the JSP is compiled and outputs an HTML form
-- the presentation. When the form is submitted, the form data is sent in a
request to /sign which is mapped to a servlet, SignGuestbookServlet, and
it's the servlet (not the JSP) which takes care of verifying authentication
and writing the data to the datastore. This is a fairly common pattern for
Java-based web applications and is not GAE-specific.Here's more detailed info.: http://java.sun.com/developer/technicalArticles/javaserverpages/servlets_jsp/ - Jason On Sun, Oct 18, 2009 at 8:04 PM, Hung <[email protected]> wrote: > > So i've been a little confused about the different responsibilities of > Servlets versus JSP. I'm very new the GAE and got confused when > looking at the guestbook tutorial. It seems that > GuestBookServlet.java has no responsibilities after guestbook.jsp was > created. However, the mapping of it in the xml says otherwise. I > know we should keep responsibilities between levels separate and it > seems to me that the JSP should be responsible purely with the user > interface and the servlets should be in charge of compiling all the > data and deciding which datastore object i should be storing it to. > > If anyone could help clear this up for me that would be really > helpful. > > Thanks > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en -~----------~----~----~----~------~----~------~--~---
