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Q:
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A:
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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.
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[ Received from Ramakrishna Potluri ]
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Q:
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A:
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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.
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[ Received
from Dhiraj Sharma]
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Q:
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A:
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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.
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[
Received from Dhiraj Sharma]
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Q:
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A:
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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\" />.
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[
Received from Dhiraj Sharma]
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Q:
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A:
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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.
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[
Received from Dhiraj Sharma]
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Q:
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A:
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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.
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[
Received from Dhiraj Sharma]
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Q:
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A:
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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.
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[
Received from Dhiraj Sharma]
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Q:
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A:
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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.
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[ Received
from Dhiraj Sharma]
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Q:
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A:
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Following tag
displays all the errors:
<html:errors/>
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[ Received from Dhiraj Sharma]
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Q:
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How you will
enable front-end validation based on the xml in validation.xml?
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A:
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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.
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[ Received
from Dhiraj Sharma]
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Q:
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A:
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We can get the values in the action
classes by using data.getParameter(\"variable name defined in the
velocity page\");
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