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.
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.
Q: How you will make available any Message Resources Definitions file to
the Struts Framework Environment?
A: 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" />
Q: What is Action Class?
A: The Action is part of the controller. 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. The ActionServlet (commad)
passes the parameterized class to Action Form using the execute() method. There
should be no database interactions in the action. The action should receive the
request, call business objects (which then handle database, or interface with
J2EE, etc) and then determine where to go next. Even better, the business
objects could be handed to the action at runtime (IoC style) thus removing any
dependencies on the model. 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.
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.
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.
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.
Q. How you will display validation fail errors on jsp page?
A: Following tag displays all the errors:
<html:errors/>
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.
NEXT
