Introduction to Struts 2.0

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Introduction to Struts 2.0

• Jenny Ni
• Joey Feng
• Winddays Wang
• Hewmmi Zhu
• Heather Lv

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Contents

1. What is Struts?
2. Why to use framework?
3. Struts 2.0 Overview
4. Struts 2.0 MVC components
5. Request Lifecycle in Struts 2
6. Struts 2.0 Architecture
7. Sample Application
8. Why we should use Struts 2.0?
9. Struts 1.x vs Struts 2.0
10. What you need to start using Struts2.0

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What is Struts?

• Open Source java framework for creating web
  applications.
• Action Based Framework
• Create web application using MVC 2 architecture
• Apache Struts offer two major version
• Struts 1.x
• Struts 2.0
• Struts 2 WebWork Struts

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Why use framework?

• Do we need framework?
• No and Yes.
• No.
• In small applications where you dont want the
  overhead of learning new things.
• But
• Yes
• We have to use framework in real world
  application because-
• Automation of common tasks
• Concentrate on higher level concerns.

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Struts 2.0

• Complete new framework based on webwork
  framework.
• Struts 2.0 implements MVC 2 design pattern.

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Struts 2.0 MVC Components

• Controller-
• Filter Dispatcher-
• First component that start processing that is why
  this type of MVC is called front controller MVC
• Looks at the request and apply the appropriate
  action.
• Struts framework handles all of the controller
  work.
• Its configured in web.xml
• Interceptors-
• Can execute code before and after an Action is
  executed.
• They can be configured per action basis.
• Can be used for data validation, file upload,
  double submit guards.

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Struts 2.0 MVC Components contd.

• Model-
• Implemented by action class
• For model you can use any data access
  technologies like JDBC,EJB,Hibernate
• View
• Its your result part. It can be JSP,JSTL,JSF etc.
• Presentation part of the MVC

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Request Lifecycle in Struts 2.0

• User Sends Request
• Filter Dispatcher determines the appropriate
  action
• Interceptors are applied
• Execution of action
• Output Rendering
• Return of Request
• Display of result to user.

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Struts 2.0 Architecture
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Struts 2.0 Architecture
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Why we should use Struts 2.0?

• Simplified Design
• Simplified Action
• Simplified Testability
• Better tag features
• Annotation introduced
• Easy plug-in
• AJAX Support

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Struts 1.x vs Struts 2.0

• How Struts 1.x and Struts 2.0 differ from each
  other?
• Configuration
• Action Class
• Dependency injection.
• Servlet Dependency
• Validation
• Threading model
• Testability
• Expression Language

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• Struts 1
• Action ?
• ActionForm ?
• ActionForward ?
• struts-config.xml ?
• ActionServlet ?
• RequestProcessor ?

• Struts 2
• Action
• Action or POJOs
• Result
• struts.xml
• FilterDispatcher
• Interceptors

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What you need to start using Struts 2.0?

• Java 5.0
• Tomcat 5.x(Servlet api 2.4 and jsp api 2.0)

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Lets see something real
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Web, Mail 2000
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Web, Mail 2009
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Struts Plugins
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Simple Example
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Struts 1
lthtmlerrors/gt lthtmlform action"/SaveMeeting"gt lt
table border"0" width"100"gt lttrgt ltth
align"right"gt Name lt/thgt lttd
align"left"gt lthtmltext property"name"
size50 /gt lt/tdgt lt/trgt lttrgt ltth
align"right"gt Date
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lt/thgt lttd align"left"gt lthtmltext
property"date" size"50"/gt lt/tdgt lt/trgt lttrgt
ltth align"right"gt Invitees lt/thgt lttd
align"left"gt lthtmlselect property"invitees"
multiple"true"gt
lthtmloptions collection"employees"
property"value"
labelProperty"label"/gt lt/htmlselectgt
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lt/trgt lttrgt ltth align"right"gt Description
lt/thgt lttd align"left"gt lthtmltextarea
property"description"
rows"4" cols"50" /gt lt/tdgt lt/trgt lttrgt lttd
align"right"gt nbsp lt/tdgt
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lttd align"left"gt lthtmlsubmit
property"DO_SUBMIT"gt Save
lt/htmlsubmitgt lt/tdgt lt/trgt lt/tablegt lt/htmlformgt

• ...
• Only four pages!

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Struts 2
ltsform action"Meeting" validate"true"gt
ltstoken /gt ltstextfield labelName
namename /gt ltstextfield labelDate"
name"date"/gt ltsselect labelInvitees
name"invitees" list"employees"/gt ltstextarea
labelDescription name"description"
rows"4" cols"50" /gt ltssubmit
valueSave" method"save"/gt lt/sformgt
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Example Revisited
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ltstextfield label"Name" name"name"
tooltip"Meeting name" /gt
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ltsdatepicker label"Date" name"date"/gt
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ltsoptiontransferselect ... /gt
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ltjspinclude page"/ajax/commonInclude.jsp"/
gt ... ltstextarea theme"ajax" label"Description"
name"description" rows"4" cols"50" /gt
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But there's more . . .
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Brian Kernighan Law of Debugging Difficulty

• Debugging is twice as hard as writing the code in
  the first place. Therefore, if you write the code
  as cleverly as possible, you are, by definition,
  not smart enough to debug it.

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Prevention and Cure
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struts.devMode true
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Built-in Testing Support
public class MyActionTest extends
StrutsTestCase public void testExecute()
throws Exception assertTrue(true)
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any.action?debugconsole
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any.action?profilingyes
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Time to Upgrade?
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Tutorials, Guides, and FAQs
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Struts 2 Training Course
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Run Struts 1 Actions as Is
ltaction name"editGangster"
class"org.apache.struts2.s1.Struts1Action"gt
ltparam name"className"gt com.mycompany.gangst
as.EditGangsterAction lt/paramgt ltresultgt
gangsterForm.jsp lt/resultgt lt/actiongt
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How do I get started?
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Where We are Going