Struts Ppt 1

Struts Agenda
 Software Crises
 What is Framework
 Model1,Model2
 What is Struts
 Why we need it
 Why is it called as
Struts
 Advantages of
Struts
 Controller
Elements & it’s
Responsibilities
 Model Elements &
it’s
Responsibilities
 View Elements &
it’s


Challenges Exist In Software
Development &
Software Crisis
* Time shown with out day light savings
 Projects must be developed
Quickly.
 Projects must be in High-Quality.
 Application Stability.
 Better code Maintainability.
 Lower Cost for Developing
Application.

What is Framework
 A software framework is a re-usable
design for a software system (or
subsystem).
 A framework is a pre-built assembly
of components and is designed to
be extended.
 It is also base for components.

Advantages of Framework
 Provide a procedure for the
development of Application.
 Saves developers Time.
 Provides same approach for all
developers for developing code and
Consistency in Software Design
 Provide low-level services that
developers can use to speedup
development.
 It also reduces software development
and maintenance costs.

Model 1
 In the Model 1 the
JSP page is
responsible for
processing the
incoming request
and replying back to
the client.

Disadvantages of Model1
 It does not have
separate
controller
 This Architecture
usually leads to a
significant
amount of Java
code embedded
within the JSP
page
 Model 1
Developers Designers
JSP
 Developers and designers
must work on the same files!

Model 2
 This Model2 approach
combines the use of
both servlets and JSP,
using JSP to generate
the presentation layer
and servlets to perform
process-intensive tasks.
 Model2 architecture
introduces a Servlet
between the
browser and the
JSP pages.

Model2 Advantages
 No processing/business logic within
the JSP page.
 Model 2 applications are easier to
maintain and extend, because views
do not refer to each other directly.
 The Model 2 controller servlet
provides a single point of control for
security and often encapsulates
incoming data into a form usable by
the back-end MVC model.
 It also Provides unique responsibility
to each component and each is

Model 2 Components and
Responsibilities  Model
 The Model portion of an
MVC-based System
responsible for internal
state of the system, and
actions that can be taken
to change that state
 Decide “How to do”
Controller
 -Decide “What to do”
 -The Controller portion of
the application is focused
on receiving requests
from the client ,deciding
what business logic is to
be performed ,and then
delegating responsibility
for producing the next
phase of user interface to
an appropriate View

What is Struts
 An open source web application
framework based on j2ee and java
which implements the MVC design
pattern is called Struts.
Why is it called as Struts
Strut synonym is Iron-rod.

Why we use and what are the
advantages of Struts
 It is open source.
 Provides components for building
Web Applications that speedup
development and saves time for
developers.
 It makes complex applications into
simple.
 Built in Exception Handling
 I18n support with resource bundles.
 Built in validation framework.

Struts Framework
Components
 Controller Components - Direct the
Action
 Model Components - Access
Data and
Systems
 View Components - What the
users see

Struts Controller Components
Struts-config.xml

Actionservlet and
Requestprocessor
 Receive the
HttpServletRequest
 Automatically
populate a
JavaBean from the
request
parameters.
 Handle Locale
Issues
 Determine which
 Extends
javax.servlet.http.HttpSe
rvlet
 Receives all framework
requests
 Selects proper
application module
 Delegates request
handling to the
RequestProcessor
instance
 One ActionServlet

Actionservlet and
Requestprocessor
 ActionServlet dispatch request to Request
Processor(New from 1.1. previous this
behaviour was in Action servlet)
 The work of Request Processor is:-
 Finding ActionMapping.
 Mapping Action to FormBean.
 Creating FormBean Object.
 Calling reset() method of FormBean
 Calling Validator of FormBean
 If no form(jsp/html) validation errors calls execute
method in Action Class and finding response to
request.

What is An Action Class
 Extends
org.apache.struts.action.Actio
n
 Overrides the execute() method
 Acts as a bridge between user-
invoked URI and a business
method
 Return information about which

Struts-Config.xml
 The power and
flexibility of struts is
due to the extracting
of configuration
information from
across frame work.
 Configuration file
contains action
mappings
(determines
navigation)
 Controller uses
mappings to turn
 Tags in this file
are:-
 Data Sources.
 Form Beans.
 Global Exceptions.
 Global Forwards
 Actions
 Controller
 Message resources
 Plug-in
Struts-Config.xml

The Model Components Model Components
 Java classes
 middle tier components
(EJB, Javabeans, …)
 database access
components
Used to represent the
Internal state of the
system
 Actions that can
change that state
 Internal state of system
represented by
 JavaBeans

Action Form Extends the ActionForm class
 Create one for each input form in the application
 It is just like a java bean, Store data temporary,
reset default values to views, validate input view.
 Hold state and behavior for user input.
 If defined in the ActionMapping configuration
file, the Controller Servlet will perform the
following:-
 Check for instance of bean of appropriate class
 If no bean exists, one is created automatically
 For every request parameter whose name corresponds
to the name of a property in the bean, the
corresponding setter method will be called
 The updated ActionForm bean will be passed to the
Action Class execute() method when it is called,
making these values immediately available.
ActionForm Example

Struts JSP Tag Libraries
 HTML
 Bean
 Logic
 Nested
 Tiles
 Template

Html Tag & Bean Tag Libraries
 Tags used to
create Struts
input forms
 Examples
(checkbox,image,
link, submit ,text,
text area)
 Tags used for
accessing
JavaBeans and
their properties
 Examples
(Define,message,
write)

Logic ,Tiles & Nested Tag
Libraries
 Managing
conditional
generation of
output text
 Looping over
object Collections
for repetitive
generation of
output text
 Example
(empty,lessThan,
greaterThan)
 Extended the base
struts tags to allow
them to relate to
each other in
nested nature
 Tiles tags
Each part ("Tile")
of webpage can be
reused as often as
needed throughout
your application.
This reduces the
amount of markup

Template Tag Library
 The "struts-template" tag library
contains tags that are useful in
creating dynamic JSP templates for
pages which share a common format.
These templates are best used when it
is likely that a layout shared by
several pages in your application will
change. The functionality provided by
these tags is similar to what can be
achieved using standard JSP include

Action Message & Action Error
 Used to signify general purpose
informational and error messages
 Rely on the resource bundles
 JSP Tags can access them
 </html:errors>

Internationalization Support
 Much of the
framework
functionality
based on
java.util.Locale
 Struts Uses Java
Resource
Bundles.
 Ex:-
 Date ,Time and
Currency

Other Features Suported by
Struts Framework
 Multi-Module Support
 Declarative Exception-Handling
 Dynamic Action Forms
 Plugins
 Tiles integrated With Core
 Validator Integrated With Core

Disadvantages
 Bigger Learning Curve
 Not Based on Domain Model
 Property Names
 Views are restricted.

Struts Ppt 1

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