| Q: |
What
is Struts? |
| A: |
The
core of the Struts framework is a flexible
control layer based on standard technologies
like Java Servlets, JavaBeans, ResourceBundles,
and XML, as well as various Jakarta Commons
packages. Struts encourages application
architectures based on the Model 2 approach,
a variation of the classic Model-View-Controller
(MVC) design paradigm.
Struts
provides its own Controller component
and integrates with other technologies
to provide the Model and the View. For
the Model, Struts can interact with standard
data access technologies, like JDBC and
EJB, as well as most any third-party packages,
like Hibernate, iBATIS, or Object Relational
Bridge. For the View, Struts works well
with JavaServer Pages, including JSTL
and JSF, as well as Velocity Templates,
XSLT, and other presentation systems.
The
Struts framework provides the invisible
underpinnings every professional web application
needs to survive. Struts helps you create
an extensible development environment
for your application, based on published
standards and proven design patterns.
|
| |
[
Received from Ramakrishna Potluri ]
|
|
| Q: |
What
is Jakarta Struts Framework? |
| A: |
Jakarta
Struts is open source implementation of
MVC (Model-View-Controller) pattern for
the development of web based applications.
Jakarta Struts is robust architecture and
can be used for the development of application
of any size. Struts framework makes it much
easier to design scalable, reliable Web
applications with Java.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
What
is ActionServlet? |
| A: |
The
class org.apache.struts.action.ActionServlet
is the called the ActionServlet. In the
the Jakarta Struts Framework this class
plays the role of controller. All the requests
to the server goes through the controller.
Controller is responsible for handling all
the requests. |
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
How
you will make available any Message Resources
Definitions file to the Struts Framework
Environment? |
| A: |
T
Message Resources Definitions file are simple
.properties files and these files contains
the messages that can be used in the struts
project. Message Resources Definitions files
can be added to the struts-config.xml file
through <message-resources /> tag.
Example:
<message-resources
parameter=\"MessageResources\"
/>.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
What
is Action Class? |
| A: |
The
Action Class is part of the Model and is
a wrapper around the business logic. The
purpose of Action Class is to translate
the HttpServletRequest to the business logic.
To use the Action, we need to Subclass and
overwrite the execute() method. In the Action
Class all the database/business processing
are done. It is advisable to perform all
the database related stuffs in the Action
Class. The ActionServlet (commad) passes
the parameterized class to Action Form using
the execute() method. The return type of
the execute method is ActionForward which
is used by the Struts Framework to forward
the request to the file as per the value
of the returned ActionForward object.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
What
is ActionForm? |
| A: |
An
ActionForm is a JavaBean that extends org.apache.struts.action.ActionForm.
ActionForm maintains the session state for
web application and the ActionForm object
is automatically populated on the server
side with data entered from a form on the
client side.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
What
is Struts Validator Framework? |
| A: |
Struts
Framework provides the functionality to
validate the form data. It can be use to
validate the data on the users browser as
well as on the server side. Struts Framework
emits the java scripts and it can be used
validate the form data on the client browser.
Server side validation of form can be accomplished
by sub classing your From Bean with DynaValidatorForm
class.
The
Validator framework was developed by David
Winterfeldt as third-party add-on to Struts.
Now the Validator framework is a part
of Jakarta Commons project and it can
be used with or without Struts. The Validator
framework comes integrated with the Struts
Framework and can be used without doing
any extra settings.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
Give
the Details of XML files used in Validator
Framework? |
| A: |
The
Validator Framework uses two XML configuration
files validator-rules.xml and validation.xml.
The validator-rules.xml defines the standard
validation routines, these are reusable
and used in validation.xml. to define the
form specific validations. The validation.xml
defines the validations applied to a form
bean.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
How
you will display validation fail errors
on jsp page? |
| A: |
Following
tag displays all the errors:
<html:errors/>
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
How
you will enable front-end validation based
on the xml in validation.xml? |
| A: |
The
<html:javascript> tag to allow front-end
validation based on the xml in validation.xml.
For example the code: <html:javascript
formName=\"logonForm\" dynamicJavascript=\"true\"
staticJavascript=\"true\" />
generates the client side java script for
the form \"logonForm\" as defined
in the validation.xml file. The <html:javascript>
when added in the jsp file generates the
client site validation script.
|
| |
[
Received from Dhiraj Sharma] |
|
| Q: |
How
to get data from the velocity page in
a action class? |
| A: |
We
can get the values in the action classes
by using data.getParameter(\"variable
name defined in the velocity page\");
|
| |
[
Received from Shri Prakash Kunwar]
|
|
