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Basic Struts work flow question

Posted on 2007-11-15
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Last Modified: 2013-11-24
Hi there,

I am new to Struts (1.2.x). 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!

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.

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?)

2. Like 1, for each action group, create an ActionForm class, like
UserActionForm

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)

4. Create a db connection by using Singleton pattern

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

6. Create 3 javabeans to map three db tables

7. Construct javabean objects based on the RecordSet returned from 5.
For example, select *  from Student will construct a Set<Student>

8. Use a loop in JSP page to get properties from the bean

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?

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?

Thanks a lot.
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Question by:tiger0516
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Accepted Solution

by:
boonleng earned 500 total points
ID: 20296021
> 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?)
There's no right or wrong doing in this way, but I prefer putting all actions for the same group in 1 class using DispatchAction, for easy manage.

Your flow seem fine. However I would suggest that you place all the database activity in DAO. To clearly define each layer.  JSP <-> Struts Action <-> DAO <- Datasource

DAO flow
---------------
   1. get connection from datasource
   2. execute SQL
   3. populate resultset to javabean.
   4. close connection on finally
   5. return javabean.

ps: suggest reading http://java.sun.com/blueprints/corej2eepatterns/Patterns/index.html You don't need to implement the full pattern, but will give you an idea how each component works.
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Author Comment

by:tiger0516
ID: 20296924
Do you have some working example code?

Thanks
0
 
LVL 14

Expert Comment

by:boonleng
ID: 20297755
You can find the sample code for DAO on Java Pet Store.
https://blueprints.dev.java.net/petstore/
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