Document

Report
Struts 2 Development
Topics
 Roles in Struts Development
 Control Flow
 Actions
 Struts 2 Views and Target
 Struts 2 Custom Tags
 Validation
 Form Submission
 Error Handling
 Resource Bundles
JSTL and JSF
Roles in Struts
Development
 Web Developer
Uses Struts custom tags, Java Server pages
and sample files to create custom web apps
Uses XML, HTML, CSS, JSP and scripting
languages to customize pages
Java Developer
programs in Java to develop Controller classes
develops Java Components (Servlets,
JavaBeans, etc.) for multi-application use
The Controller
 FilterDispatcher
 Behaves like an Action factory
Control Flow
Client
Request
FilterDispatcher
Should an
action be
invoked?
ActionMapper
Control Flow
FilterDispatcher
ActionProxy
ActionInvocation
Look up
Action class
struts.xml
Control Flow
ActionInvocation
Look up
Result Code
Action
struts.xml
execute()
The Action Class
 POJO
 Can contain an instance of the model as member
variable because Action classes are instantiated
for each request (thread-safe)
 Override the execute() method
public String execute()
 Returns a simple String that serves as a symbolic
name to determine what should happen next
Configuring the Action
Class
 Compile the new Action and put it in Web
application’s classpath
Add an <action> element to struts.xml
 Several <action> elements can use the same
Action class as long as name attribute is
different
<action name=“login”
class=“edu.weber.LoginAction”>
..
</action>
Struts 2 Views
 Composed of JSPs, custom tag libraries, and
ActionForm objects
JSPs
Present Data
Gather Data
Targets of Action result
JSP Targets
Action-Specific Forward
<action ..
..
<result name=“success”>Welcome.jsp
</result>
<result name=“error”>Login.jsp
</result>
</action>

Struts 2 Custom Tags
 Tag Library:
<%@ taglib prefix=“s” uri=“/struts-tags” %>
<s:form/>
<s:textfield/>
<s:password/>
<s:submit/>
<s:actionerror/>
Struts 2 Custom Tags
 Struts 2 utilizes FreeMarker to generate the
markup for the tags.
FreeMarker can generate any type of markup:
HTML, XSLT, WML, etc.
Validation
Validation is managed at the object level
Fields in an Action class can be checked
through configuration file:
<ActionClassName>-validation.xml
Validation Example
LoginAction-validation.xml
<!DOCTYPE validators PUBLIC
“-//OpenSymphony Group//Xwork Validator 1.0.2//EN”
http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd>
<validators>
<field name=“username”>
<field-validator type=“required”>
<message key=“required” />
</field-validator>
</field>
</validators>
Struts 2 Form Submission
 Form state/data combined with Action class
<s:form action=“login.action” method=“post”>
<s:textfield name=“username”
key=“label.username” size=“20” />
</s:form>
Struts 2 Error Handling
 Establish ActionError tag on view
<s:actionerror />
 Use addActionError to accumulate message on
ValueStack
addActionError(getText(“error.login”));
Defining Resource
Bundles
 ResourceBundle is a file which contains a
series of name/value pairs
 Naming format is
ResourceBundleName.properties
For example a file named
ApplicationResources.properties might
contain the entry
error.age.invalid=Invalid Age
Deploying
ResourceBundles
Place a copy of the resource bundles in the /WEBINF/classes directory of your web application
using appropriate package directory structure
Place the following entry in struts.xml
<constant
name=“struts.custom.i18n.resources”
value=“ApplicationResources />
Retrieving Localized
Messages
Web Page: key attribute
<s:textfield name=“username”
key=“label.username” size=“20” />
Java: getText()
getText(“promptTitle”);
JSP Standard Tag Library
(JSTL)
Establish a common set of custom tags
Create syntax that eliminates scripting within Web
pages
 Supports
 Core operations (iteration, conditionals)
 XML Processing
 Internationalization formatting
 Database access
The Jakarta Taglibs Standard 1.0 tag library is an
implementation of JSTL 1.0.
JavaServer Faces (JSF)
Component model for building user interfaces for
Web Applications
 APIs for managing UI state, handling events
and input validation, page navigation
 JSP Custom tag library
Benefits
 Ease-of-Use
 Standardization
 Device Independence
Review
 Roles in Struts Development
 Control Flow
 Actions
 Struts 2 Views and Target
 Struts 2 Custom Tags
 Validation
 Form Submission
 Error Handling
 Resource Bundles
 JSTL and JSF

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