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<document>
<properties>
<title>The Apache Struts Web Application Framework</title>
<author>Craig R. McClanahan</author>
<author>Ted Husted</author>
<author>Martin Cooper</author>
<author>James Holmes</author>
<author>David Graham</author>
</properties>
<body>
<section name="Welcome to Struts" href="Welcome">
<p>
Welcome to Struts!
The goal of this project is to provide an open source framework for
building Java web applications.
</p>
<p>
The core of the Struts framework is a flexible control layer based on
<a href="userGuide/preface.html">standard technologies</a> like Java
Servlets, JavaBeans, ResourceBundles, and XML, as well as various
<a href="http://jakarta.apache.org/commons/index.html">Jakarta Commons</a> packages.
Struts encourages application architectures based on the Model 2 approach,
a variation of the classic
<a href="http://java.sun.com/blueprints/guidelines/designing_enterprise_applications_2e/web-tier/web-tier5.html">
<strong>Model-View-Controller</strong></a> (MVC) design paradigm.
</p>
<p>
Struts provides its own <strong>Controller</strong> component and integrates with <a href="userGuide/preface.html#layers">
other technologies</a> to provide the Model and the View.
For the <strong>Model</strong>, Struts can interact with standard data access
technologies, like <a href="http://java.sun.com/products/jdbc/">JDBC</a> and
<a href="http://java.sun.com/products/ejb/">EJB</a>, as well as most any third-party packages, like
Hibernate, iBATIS, or Object Relational Bridge.
For the <strong>View</strong>, Struts works well with
<a href="http://java.sun.com/products/jsp/">JavaServer Pages</a>, including
<a href="./faqs/kickstart.html#jsf">JSTL and JSF</a>, as well as Velocity Templates, XSLT, and
other presentation systems.
</p>
<p>
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.
</p>
<p>
Struts is part of the
<a href="http://jakarta.apache.org">Apache Jakarta Project</a>,
sponsored by the
<a href="http://www.apache.org">Apache Software Foundation</a>.
The official Struts home page is at
<a href="http://jakarta.apache.org/struts">
http://jakarta.apache.org/struts</a>.
</p>
<p>
Struts is a volunteer project and all support for the framework is provided by unpaid volunteers.
This documentation bundle and the mailing lists are the primary ways to learn how to use Struts.
The next few pages are devoted to helping you understand what resources are available to you.
Since Struts is a volunteer project, and our resources are limited, it is important that we first help you
help yourself.
</p>
</section>
<section name="Struts in a Nutshell" href="nutshell">
<p>
A <a href="http://java.sun.com/webservices/docs/1.0/tutorial/doc/WebApp.html">web application</a> uses a
deployment descriptor to initialize resources like <a href="userGuide/preface.html#servlets">servlets</a>
and <a href="userGuide/preface.html#jsp">taglibs</a>.
The deployment descriptor is formatted as a <a href="userGuide/preface.html#xml">XML</a> document and named
"web.xml".
Likewise, Struts uses a configuration file to initialize its own resources.
These resources include <a href="userGuide/building_controller.html#action_form_classes">ActionForms</a> to
collect input from users,
<a href="http://jakarta.apache.org/struts/userGuide/building_controller.html#actionmapping">
ActionMappings</a> to direct input to server-side
<a href="http://jakarta.apache.org/struts/userGuide/building_controller.html#action_classes">Actions</a>,
and ActionForwards to select output pages.
</p>
<p>
Here's a simple Struts configuration (struts-config.xml) for a login workflow:
</p>
<source><![CDATA[
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
"http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd">
<struts-config>
<form-beans>
<form-bean
name="logonForm"
type="app.LogonForm"/>
</form-beans>
<action-mappings>
<action
path="/Welcome"
forward="/pages/Welcome.jsp"/>
<action
path="/Logon"
forward="/pages/Logon.jsp"/>
<action
path="/LogonSubmit"
type="app.LogonAction"
name="logonForm"
scope="request"
validate="true"
input="/Logon.do">
<forward
name="success"
path="/Welcome.do"/>
<forward
name="failure"
path="/Logon.do"/>
</action>
<action
path="/Logoff"
type="app.LogoffAction">
<forward
name="success"
path="/Welcome.do"/>
</action>
</action-mappings>
<message-resources parameter="resources.application"/>
</struts-config>
]]></source>
<p>
There are several other resources you can specify in Struts configuration files.
You can specify validations for the ActionForms in an XML descriptor, using the
<a href="userGuide/dev_validator.html">Struts Validator</a>.
Another extension, <a href="userGuide/dev_tiles.html">Tiles</a>, helps you build pages from smaller
fragments.
</p>
<p>
Struts is an extensible framework.
Every class deployed by Struts can be replaced by your own default class.
The properties of your default class can be set using the
<a href="http://jakarta.apache.org/commons/digester/"> Digester's</a> <code>set-property</code> feature.
This is one reason why there are so many <a href="resources/extensions.html">contributor extensions</a> for
Struts.
Struts provides a base framework, but you can still write <b>your</b> application <b>your</b> way.
</p>
<p>
For more about Struts and its underlying technologies, see the <a href="userGuide/index.html">User
Guide</a> and the Developer Guides.
</p>
</section>
<section name="Is Struts the best choice for every project?">
<p>
No. If you need to write a very simple application, with a handful of pages,
then you might consider a "Model 1" solution that uses only server pages.
</p>
<p>
But, if you are writing a more complicated application, with dozens of pages,
that need to be maintained over time, then Struts can help. For more about
whether Model 1 or or MVC/Model 2 is right for you, see
<a href="http://www.javaworld.com/javaworld/jw-12-1999/jw-12-ssj-jspmvc.html">Understanding JavaServer
Pages Model 2 architecture</a> and
<a href="http://www.scioworks.net/devnews/articles/struts_adoption_issues/index.html">
Issues in Struts Adoption</a>.
</p>
</section>
<section>
<p>
Next: <a href="learning.html">Learning About Struts</a>
</p>
</section>
<section>
<p>
<a href="faqs/kickstart.html#jsf">What about JSTL and JavaServer Faces?</a>
</p>
</section>
</body>
</document>