Howard Miller wrote:
That helps a lot... just one question if you don't mind... can I check how you would forward from the prepareListBookAction to the bookSearch.jsp. I assume you are just using mapping.findForward( "success" ). That didn't work for me... which is really why I started thinking that I was doing totally the wrong thing. Could (of course) be some stupid error!Yes, on successful completion, PrepareListBookAction.perform() ends with
return (mapping.findForward("success"));
If you are getting a blank page, there is most likely something wrong with your jsp. Check your container logs.
I'm off to try harder... thanks!HM On 20 Oct 2002 at 10:10, Phil Steitz wrote:Howard Miller wrote:I think I'm seriously missing the point here! I have looked at the example application in some detail and it appears to add a parameter (eg, ?action=new) to tell the action for a form to perform an initialising action. I don't see it using a "pre-" action.Here is a simple example showing one way to deal with this type of thing. There are no doubt lots of other ways to handle this.
I am incredibly stuck with the concept of how to code an action that is not encumbered with *special* parameters to pre-load the bean data. My particular problem is that I have pages where the previous page cannot be predicted, so the jsp must have a means of loading its own data.
I would really appreciated some pointers as to how to set this up. *** I particularly don't understand how to get the action to call the following JSP *** (ie, I would really appreciate some specific - example - help on this!! ). At least every method I have tried doesn't work.
Use case: library search. User page flow: main menu -> search input page (bookSearch.jsp) -> search results page (listBook.jsp). The search input page needs to be pre-populated with a list of currently defined subjects.
Struts processing flow: main menu -> search input pre-populate action (PrepareListBookAction) -> search input page (bookSearch.jsp) -> search processing action (ListBookAction) -> search results page (booklist.jsp).
In struts-config:
<!-- Prepare Book Search (populates subject list) -->
<action path="/a/prepareListBook"
name="bookSearchForm"
type="com.steitz.library.PrepareListBookAction"
validate="false"
scope="request">
<forward name="success" path="/a/bookSearch.jsp"/>
</action>
<!-- Book Search -->
<action path="/a/listBook"
name="bookSearchForm"
type="com.steitz.library.ListBookAction"
scope="request"
input="/a/bookSearch.jsp"
validate="true">
<forward name="success" path="/a/booklist.jsp"/>
</action>
In the main menu:
<a href="prepareListBook.do">
<bean:message key="index.find"/></a>
(here "index.find" = "Find a Book".)
PrepareListBookAction retrieves the list of currently defined subjects and sets a property of the (automatically created) BookSearchForm for the book search input form (bookSearch.jsp) to use.
The key concept is that instead of linking/forwarding to the input jsp directly, you link/forward to the pre-population action and then have the pre-population action set up the form bean and then forward to the input jsp.
Hope this helps,
Phil
I do understand how to actually create a bean manually and put in in the scope. I don't understand how to set up a generic preload action for a given JSP/ActionForm, and what the config should look like.
Again, any help much appreciated.
HM
On 20 Oct 2002 at 8:43, David M. Karr wrote:
Howard> Hi,"Howard" == Howard Miller <[EMAIL PROTECTED]> writes:
Howard> Can somebody kindly help me with the following...
Howard> I want to add a path and an Action class. The action class will then preload data into Howard> a bean and then forward (do I mean forward) to the jsp that displays the bean. That's Howard> it. I want this action to be in *addition* to the *normal* jsp/formbean/action setup.
Howard> I can't see how to do it.... in particular
Howard> 1. I don't think I fully understand how/why an action is associated with a bean in Howard> struts-config. What does the action servlet do with this information.
Howard> 2. How do I properly forward from an action to a jsp with the bean information intact. Howard> It seems to be very similar to an action returning its "input form" to display errors, but Howard> doing this doesn't work. Whatever I do I seem to get a blank page.
In fact, the best practice is to always preface a page with an action. You end
up with actions that prepare information for a page, and actions which process
information for a page. The actions which process the page information will
always have had the form bean created before you get to the action. However,
the actions which prepare the page information may have to manually create the
form bean and put it into the appropriate scope.
Note that the welcome page for an application would normally be something like
"index.jsp", which does nothing but forward to an action to start the
application. You can't preface the welcome page with an action, but you can
make it do nothing but go to an action to prepare the real first page.
Look at the source code for the "example" application for some examples of
using the form bean. The user guide also talks about the control flow with
respect to form beans.
--
===================================================================
David M. Karr ; Java/J2EE/XML/Unix/C++
[EMAIL PROTECTED]
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