Before starting Struts3 Frameworks we need some pre requirement .We require some basic knowledge of 
J2SE, 
JDBC, 
HTML, 
CSS, 
JavaScript, 
JSP/Servlet,
 J2EE 
TomCat or any Application Server( or similar type of server).

 
Pre-requirement Knowledge:-
Core Java 
JDBC
Collections 
JSP
Servelet 
J2EE (with regards to Web applications)
Tomcat Server or any Application Server
HTML/CSS/JavaScript/XML
Hardware:-Struts2 does not required any special Hardware.

Java Development Kits:- JDK1.5: You can download Java Development Kits from http://developers.sun.com/downloads/

Struts Frameworks (Jars):- You can download Apache Struts2 http://struts.apache.org/

Servers Tomcat:-You can download Apache Tomcate http://tomcat.apache.org/

Server GlassFish Server:-You can download open source GlassFish Server http://glassfish.java.net/public/downloadsindex.html

IDEs:-Today all companies are using following IDEs for create, run and debugs a Struts2 application. You can use notepad or any other IDEs .But we suggest use one of following two--
Eclipse You can download eclipse http://www.eclipse.org/downloads/
NetBean You can download NetBean IDE from http://netbeans.org/downloads/index.html
 Operating System Environments:-Struts application can make run and debug on Window/Linux




Struts 1.3 Tutorial and Example
Spring 2.5 Tutorial and Example
Spring 2.5 MVC Tutorial
Spring 2.5 MVC Example