Responses inline...
-----Original Message-----
From: Minghui Yu [mailto:[EMAIL PROTECTED]
Sent: Thu 11/15/2007 7:16 PM
To: Struts Users Mailing List
Cc:
Subject: Basic Struts work flow question
Hi there,
I am new to Struts (version 1.2.7). I am developing a small app to
learn Struts. Could you please give me some suggestions? Many thanks!!
Scenario:
A very small web app. I have 3 tables: student, course, and student-
course. Student and course are 1:N relationship. student-course is a
bridge table, which takes user_id (from Student) and course_id (from
Course) as FKs. Anonymous users can view, registered users can edit,
admin can add,delete and edit. That's it!
EG>Decide how you separate anonymous pages vs registered user pages.
EG>Are you protecting them via a role and constraints in web.xml?
As I am brand new to Struts, I do not want to use Hibernate or another
framework. I just want basic JDBC for db work.
EG>Probably a bad idea. At the very least, look at iBATIS. It will
save you time.
EG>Look at the Struts CRUD demo at www.learntechnology.net
My ideas:
1. For each action group (instead of individual action), create an
Action class. For example, UserAction (add,edit,delete users) instead
of UserAddAction, UserDeleteAction, UserEditAction. Is this a good
practice or not? Or shall I create an Action class for each individual
action (will that bring a lot repetitive codes?)
EG>I'd stick with one action, and make use of a flavor of dispatch
action, or
EG>use EventDispatchAction.
2. Like 1, for each action group, create an ActionForm class, like
UserActionForm
EG>You may not need to if you look into FormDef or use DynaActionForms.
3. Create a JSP page for each individual action (not group) as the
input/entry page. For example, addstudent.jsp, deletestudent.jsp,
editstudent,jsp. Each JSP page use corresponding ActionForm bean. For
example, the above three JSP pages all use UserActionForm. However,
different JSP pages use different element of the ActionForm bean. For
example, user_id is not used in addstudent.jsp but is used in
deletestudent.jsp, as an id is required to delete a record but not
required to add one (I set id, the PK for Student table as auto-
increasement)
EG>Just don't ever let anyone see the id#. It should never appear as a
hidden field.
4. Create a db connection by using Singleton pattern
EG>Ibatis will handle all the connection stuff for you, just create the
singleton
EG>for getting the SQLMAP Client instance.
5. For each Action class, depending on different inputs, prepare sql
statement and pass the statement to the db connection created in 4.
Get a RecordSet as returned value
EG>You should not be passing SQL statements around at all.
EG>Read about DAOs, or just create a service/business related class that
EG>performs these interactions with the database rather than coding them
EG>directly into the actions. An action need not establish a
connection at all.
6. Create 3 javabeans to map three db tables
EG>Sounds ok.
7. Construct javabean objects based on the RecordSet returned from 5.
For example, select * from
Student will construct a Set<Student>
EG>These can be properties of the forms, so you need not have
additional objects.
EG>Ibatis can automatically handle returning a resultset as an
ArrayList.
EG>You can also look into the RowSetDynaBean (or disconnected rowset).
8. Use a loop in JSP page to get properties from the bean
EG>Use Struts Logic or JSTL c:foreach.
That's my basic view on Struts. I have no idea if my view is okay or
bad. Could you please give me some help?
EG> That's all I have for now. It sounds like you are starting ok.
Additionally, I am not sure how to close the db connection,.as I need
to call the db many times. Within the Singleton patten db connection
class, as I need to return the RecordSet, how shall I close the db?
What shall be the order/sequence to do that?
EG>That's why you use a framework. The iBATIS tutorial (quickstart) is
only
EG>about 10 pages, so it's well worth looking into. If you know SQL,
which
EG>you'd have to if you were going to use JDBC, then look at iBATIS.
EG>The above is opinion only - take it for what it's worth, and good
luck.
Thanks a lot.
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