Struts 2 Overview, Struts is an open source framework which was built by Craig McClanahan to develop MVC web applications, later on it was given to the Apache foundation in May 2000 then the stable version of Struts was released in June 2001 with features and later on struts2.0 released in 2014, present version of Struts2 is 2.5.2. To understand the concept of Stuts2 user need to have little knowledge on Servlet, JSP, MVC. The advantage of Struts is that integration with other frameworks such as Spring, Hibernate.
Struts2 Framework act as MVC (model and view controller). Configuration of all the information about views and controllers is done in Struts.XML file. One can modify any data without changing the entire application by changing the XML file.
Advantages
In Struts2, POJO class work as action class. This class cannot be extended or cannot implement any interface on that class and cannot create the formBean class separately.
Struts2 supports the AJAX framework. AJAX is used to make an asynchronous request. Then, if one uses any validations it can perform very easily.
Struts2 Framework defines some predefined tags like Control tags, Data tags, UI tags. These tags are defined in view pages.
Struts2 provides some Themes and Template support. These themes are used to see the output in a browser which makes it easily understandable. It provides three types of themes XHTML, simple and css_html.
Struts2 framework is easily integrated with the other framework like Hibernate, Spring, Tiles.
In Struts2, number of plugins are available.
Struts2 supports multiple view options like JSP, Freemarker, Velocity, XSLT.
Disadvantages
Not easy to understand: Compare to other technologies Struts framework is more difficult why because no one can not work on struts directly, before dealing with struts developer must have a knowledge with Servlet, JSP.
Migration Problem: Struts 2 and Struts 1 both are completely different so migration of developed applications are not possible.
JAR file required problem
XML configuration file
Bigger Learning Curve
Summary
Key Points
Struts 2 Overview - Limited documentation is the prime disadvantage of Struts 2
Struts 2 Overview - Migration of an application from Struts 1 to Struts 2 is very difficult.
Struts 2 Overview - Struts will have lengthy learning curve so its mandatory to have a knowledge on Servlets and JSP.