Introduction to Struts

1
Introduction to Struts
2
What is Struts

• Framework to develop web applications
• Open source
• Based on MVC-Model 2 pattern
• Apache Jakarta Project
• Current release is 1.2.7
• Developed in May 2000 and June 2001

3
What is Frame work

• Frameworks are reusable, semi-complete''
  applications that can be applied to produce
  custom applications
• Frameworks are tested, proven software designs
  and implementations that reduce the cost,
  accelerate development speed and improve the
  quality of software

4
Benefits of Struts Frameworks

• Provide developers with modular, reusable and
  extensible software components
• Modular frameworks reduce the time and effort and
  investment required to understand and maintain
  existing software

5

• Contributes improvements in programmer
  productivity, as well as enhancing the quality,
  performance, reliability of the software.
• Reduces the cost of building and maintaining
  software

6
What is the MVC Pattern?

• MVC was first introduced by SmallTalk
• The goal of the MVC design pattern is to separate
  the application object (model) from the way it is
  represented to the user (view) from the way in
  which the user controls it (controller) i.e.
  layer architecture.

7
Components within the MVC Pattern?

• The model provides a representation of the data
  to the components comprising the view. It also
  knows about all the operations that can be
  applied to transform the data.
• The view provides presentation services in the
  application, such as a data entry screen or a
  screen rendering a query result .

8

• The controller is responsible for linking the
  view with the model. The controller can be
  thought of as the controlling influence on the
  state of the model. All paths of navigation in
  the application are channelled through the
  controller.

9
What is MVC-Model 2
Business Layer
Controller Servlet
Form submit HTTP Event
Create/Set property
Model JavaBean
Browser
Forward
View JSP HTML Stylesheets
Get property
HTTP Response
10
What is Struts MVC-Model 2
Business Layer
create
ActionForm
Controller ActionServlet
Http Event
Business Logic Action
dispatch
Browser
Struts- Config. xml
create/set
forward
Model JavaBean
Resource Bundle
forward
View JSP
Http Response
get
11
What is Struts Architecture?

• The model is comprised of a combination of EJBs,
  Java Beans, and a set of Java classes extending
  the Struts base class ActionForm
• The view is represented by JSPs.
• The controller is implemented by the Struts
  ActionServlet.

12

• You can extend the controllers behavior by
  creating Action classes to trigger the execution
  of a user request.

13
How to build a Struts application?

• Build the Model Components (ActionForm Class)
• Build the Controller Components (Action Class)
• Build the View Components (JSPs)
• Create the struts-config file
• Update the web.xml file

14
Building an ActionForm

• The ActionForm (also called the form) is a data
  holder that contains the data entered trough an
  HTML form.
• The form should also contain the get set
  methods for each property.
• The form may also implement a validate method to
  perform data entry validations before actually
  performing the requested action.
• To create a form, you will need to extend the
  class org.apache.struts.action.ActionForm

15
Building an ActionServlet

• ActionServlet is used to control the request and
  send the appropriate response to that request.
• It transforms request parameters into ActionForm
• There is only one ActionServlet in the
  application.
• Package is used org.apache.struts.action.ActionSer
  vlet

16
Building a JSP

• To create a JSP using Struts you will use the tag
  libraries provided by the Struts Framework.
• struts-logic.tld This tag library contains tags
  that are useful in managing conditional
  generation of output text, looping over object
  collections for repetitive generation of output
  text, and application flow management.
• struts-html.tld This taglib contains tags used
  to create struts input forms, as well as other
  tags generally useful in the creation of
  HTML-based user interfaces.

17
Create the struts-config.xml file

• To allow for better reusability, all components
  in Struts are loosely coupled.
• To integrate the components you must create a
  config file (struts-config.xml)
• Within this file youll define the
  action-mappings and form-beans.
• The action-mappings tell the ActionServlet which
  action classes to include within the application.
• The form-beans define the ActionForm classes
  required within the application.

18
Other Resources

• Struts homepage
• ttp//jakarta.apache.org/struts/
• The Jakarta Project
• ttp//jakarta.apache.org
• Search on ttp//www.google.com
• Search criteria jakarta struts

19

• Thanks
• Yashwant Chavan.
• ITShastra (INDIA) Pvt. Ltd.