Struts – An implementatiion of MVC2
As discussed in the previous section about MVC2, there is central controller associated with all views and models. Similarly, Struts has central controller called as ActionServlet, which receives requests from all the JSP Pages (View) and forwards them to appropriate Model called as Action and vice versa. To put it in Struts framework terms, org.apache.struts.action.ActionServlet is the backbone of all Struts applications. It is the main Controller that handles client request and determines which org.apache.struts.action.Action to call to process each received
request. This logic of associating a client request to particular Action, an ActionServlet takes from a configuration file called strus-config.xml.
Fig 3 below shows how Struts framework is the prefect implementation of MVC2.
Why Sttrutts
Today’s web applications are critical components of the corporate mission. As always, development teams need to build applications in record time, but they have to build them right and build them to last.
Java web developers already have utilities for building presentation pages, such as JavaServer Pages and Velocity templates. We also have mechanisms for handling databases—JDBC and Enterprise JavaBeans (EJBs), for example. But what do we use to put these components together? We have the plumbing and the drywall … what else do
we need?
One step back, three steps forward
In the late 1970s, when graphical user interfaces (GUIs) were being invented, software architects saw applications as having three major parts: the part that manages data, the part that creates screens and reports, and the part that handles interactions between the user and the other subsystems [Ooram]. In the early 1980s, the ObjectWorks/Smalltalk
programming environment introduced this triumvirate as a development framework. In Smalltalk 80 parlance, the data system is dubbed the Model, the presentation system is called the View, and the interaction system is the Controller. Many modern development environments, including Java’s Swing, use this Model/View/Controller (MVC) architecture as the foundation of their own frameworks.
Java web developers already have capable tools, such as JDBC and JSP, for consulting the Model and creating the View, but where’s the Controller for our web applications?
Enter Struts
The centerpiece of Struts is an MVC-style Controller. The Struts Controller bridges the gap between Model and View. The framework also includes other missing pieces developers need to write scalable, leading-edge web applications. Struts is a collection of “invisible underpinnings” that help developers turn raw materials like databases and web
pages into a coherent application.
April 12, 2007
Struts