The Figure below clearly depicts the exact evolution of web application all the way from its humble beginning in early 90’s to the current state.
It’s very hard to clearly separate Web 1.0 from web 2.0 as there wasn’t anything different which got introduced in Web 2.0. That’s the reason the figure above clearly doesn’t put in a timeline as these are not very clearly defined. Having said that, it evident from the figure that, over the last few decades there has been substantial change in how we see web sites/ applications. When the web initially started, these were not called as applications; rather these were called as sites, with static content and hyperlinks which allows users to navigate from one content page to another. After that came the existence of CGI and Servlets which allowed these static sites to become dynamic and more personalized. These sites slowly started calling themselves as applications as they start to do some basic stuff which a client server application could do for a user. The scene of web applications quickly changed with the introduction of MVC frameworks (In the world of Java Struts was one of the initial MVC frameworks) and the templating engines. These changed the way we looked at web applications and there was a huge rise in people adopting it to make web applications for businesses. With the introduction of Web 2.0 standards, another important addition to the web came into existence in the form of AJAX, which helped web applications to render parts of its page rather than generating the whole page at once. This made web more rich, faster and importantly brought about good user experience. With web 2.0 came into existence new standards (HTML5, CSS3 etc.) and these completely changed this space and a new paradigm shift began to be thought through in the form on client side MVC frameworks.
Disclaimer: The chapter have been written with figures sourced from various on-line materials. I haven’t been bale to attribute these figures with source. Really apologize for this. In case anyone has any issues in me using the figures and content, please drop an email to me at tomcyjohnatgmail.com. I will make sure that the details are either attributed or the image/content removed from my blog post. Thanks in advance.
Spring Framework’s web application support is through two sub-projects namely Spring MVC and Spring Web Flow.
Spring Framework has its own MVC based web application framework in the form of Spring MVC. They conceived and developed its web framework to address some of the deficiencies and poor design consideration in other popular framework available in the market. One of the main deficiencies identified was the lack of separation of concerns like proper separation between the presentation and request handling layer and between request handling layer and the model layer. Similar to Struts, Spring MVC is a request-based web application framework. Spring MVC makes sure that all the interfaces are tightly coupled with the core Servlet API’s rather than the Spring API’s.
Spring Web Flow is one of the sub-project which aims at providing the infrastructure for developing and running web application. It tries to aid web application developers in defining appropriate navigation rules, manage navigation and conversational state as well as facilitating high level reuse and modularization.
Spring MVC as well as Spring Web Flow is a very huge topic to cover in one Chapter. There are books written only on these topics. I would cover some basic concepts of both Spring MVC and Spring Web Flow in this Chapter. The first part of this Chapter makes you walk through Spring MVC and the second part of this Chapter walks through Spring Web Flow. I will try to cover basic detail of both frameworks so that you will get a heads up on these and can start off developing using these.
Spring MVC allows you to build extensible, robust and loosely coupled MVC-based web application. With the use of the famous Model-View-Controller pattern, it inherently brings separation of the various layers in a typical web application namely business, presentation and navigation in a clear way.
We have covered MVC pattern in detail in this book, but just to refresh your mind, the responsibility of Model is to encapsulate the application data, the responsibility of View is to render the response to the user with the help from the Model object and the responsibility of Controller is to receive the request from the end user and transfer it to the back-end services which will populate the Model objects and sends the view object to the user.
Figure 14-1. Spring MVC’s fit in an enterprise application containing other layers