Struts Interview Questions
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.
What is Struts?
What is Jakarta Struts Framework?
What is ActionServlet?
How you will make available any
Message Resources Definitions file to the Struts Framework Environment?
What is Action Class?
What is ActionForm?
What is Struts Validator
Framework?
Give the Details of XML files
used in Validator Framework?
How you will display validation
fail errors on jsp page?
How you will enable front-end
validation based on the xml in validation.xml?
How to get data from the velocity
page in a action class?
What is Struts?
What is Jakarta Struts Framework?
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.
What is ActionServlet?
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.
How you will make available any
Message Resources Definitions file to the Struts Framework Environment?
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\" />.
What is Action Class?
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.
What is ActionForm?
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.
What is Struts Validator
Framework?
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.
Give the Details of XML files
used in Validator Framework?
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.
How you will display validation
fail errors on jsp page?
Following tag displays all the
errors:<html:errors/>
How you will enable front-end
validation based on the xml in validation.xml?
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.
How to get data from the velocity
page in a action class?
We can get the values in the
action classes by using data.getParameter(\"variable name defined in the
velocity page\");
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