Getting Started

Preface

Struts Action Framework 2 is a popular, easy-to-use MVC framework. This tutorial will help you get started with the framework, even if you are not an experienced Java web application developer. The tutorial will walk you through installing the framework and creating a simple application.

However, the framework is geared toward professional developers. To create non-trivial applications, a working knowledge of several key technologies is required.

For more about any of the supporting technologies, visit the Key Technologies page on the Apache Struts website.

In this lesson, we download the framework, launch the example applications, and then get started on an application of our own.

Download the Distribution

The full distribution can be downloaded form the Apache Struts website. The distribution contains the struts-action2.jar file, a copy of all the documentation, sources, all required and optional dependencies,and example applications. For more information on how to build the framework from source or even from a clean checkout, please refer to Building the Framework from Source.

Your First SAF2 Application

To get started on your own application, you can utilize the blank template, run the Ant task, or just setup your own from scratch.

Using the Blank template

The blank web application in the distribution's webapp directory is meant as a template. Make a copy of "blank" and use the copy as the basis for your application.

Run the Ant task

While it's simple enough to copy a directory tree, there is an even easier way to get started. In the webapps directory, there is a build.xml file. The new task of this Ant build file can create fresh, empty web application for you. Just add content!

> cd /projects/Apache/struts-current/action2/webapps
> ant new

The Ant buildfile will prompt you for a the name of your new application.

new:
     [echo]
     [echo]             +=============================================================+
     [echo]             |              -- Create a new web application  --            |
     [echo]             +=============================================================+
     [echo]

    [input] Enter the name of your new application [myapp]? saf-sample
     [echo] Creating 'saf-sample' web application...
     [copy] Copying 7 files to /Users/rainerh/projects/action2/webapps/saf-sample
     [copy] Copying 1 file to /Users/rainerh/projects/action2/webapps/saf-sample
     [echo]
     [echo]             +=============================================================+
     [echo]             |    -- Your Web Application was created successfully! --     |
     [echo]             |                                                             |
     [echo]             | Now you should be able to cd to your application and run:   |
     [echo]             | > ant build -Dwebapp=saf-sample                              |
     [echo]             +=============================================================+

BUILD SUCCESSFUL

This task creates a new directory within the webapps dir.

For example, this is the setup for a new webapp project created with ant new webapp name saf-sample:

webapps/
  saf-sample/
    src/
      java/
         org/apache/struts/action2/example/HomeAction.java -- A simple action example implementation
      webapp/
        index.jsp -- redirects to home.action
        WEB-INF/
          classes/
            action.properties -- Simple properties to use Spring and run SAF in devMode
            action.xml -- Basic action mapping sample with one action mapping
          pages/
            home.jsp -- The home.jsp referenced via the HomeAction
          applicationContext.xml -- blank Spring definition file. Add your Spring beans here.
          web.xml -- basic web.xml for SAF

You can now use the newly created project structure to get your SAF-based project running.

Setting up from scratch

If for some reason the blank template doesn't work for you, it's not so hard to setup a SAF-based application from scratch.

Structure of your web application

• Setup a file structure for your application.

/mywebapp/
/mywebapp/template/
/mywebapp/META-INF/
/mywebapp/WEB-INF/
/mywebapp/WEB-INF/classes/
/mywebapp/WEB-INF/lib/
/mywebapp/WEB-INF/lib/CORE&OPTIONAL *.jar
/mywebapp/WEB-INF/web.xml

• Copy to your webapp/lib directory
  • the struts-action-(VERSION).jar,
  • all the *.jar files in /lib/default, and
  • any necessary optional *.jar files from /lib/.

If you need to customize your own templates (how HTML is rendered from webwork UI tags), copy into your webapp directory the /src/java/template directory.

Minimum set of libraries and configuration files

The following files are a minium requirement for your application.

The library files (*.jar) needs to be copied to your /mywebapp/WEB-INF/lib/ directory. If you need optional functionalities requiring dependencies on optional JARs, those JARs need to be copied to this directory too.

Setup web.xml

Create an web.xml file in [webapp]/WEB-INF (or merge into it the framework resources).

<?xml version="1.0"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
  <display-name>My Application</display-name>
  <filter>
    <filter-name>action2</filter-name>
    <filter-class>org.apache.struts.action2.dispatcher.FilterDispatcher</filter-class>
  </filter>

  <filter-mapping>
    <filter-name>action</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
</web-app>

The standard web.xml registers a FilterDispatcher to enable framework functionality for your requests. The ContextLoaderListener configures Spring as our dependency injection conitainer. The framework uses Spring internally, and you may wish to use it to deploy your own objects.

See also: web.xml

Setup action.xml

Create a skeleton action.xml file in /$APP/WEB-INF/classes.

<!DOCTYPE xwork PUBLIC "-//OpenSymphony Group//XWork 1.1.1//EN"
"http://www.opensymphony.com/xwork/xwork-1.1.1.dtd">

<xwork>	<!-- Include framework defaults (from Struts Action JAR). -->
	<include file="action-default.xml" />

	<!-- Configuration for the default package. -->
	<package name="default" extends="action-default">
	</package>
</xwork>

For now, the action.xml does only two things:

• It tells the framework that it should import the configuration information from action-default.xml. (This file is located at the root of the struts-action.jar, so it is sure to be found.)

• It defines a default package (with the <package> section) where framework elements like actions, results and interceptors are registered.

See also: action.xml