Spring MVC Framework

Spring’s Web MVC framework is designed around a DispatcherServlet that dispatches requests to handlers, with configurable handler mappings, view resolution, locale and theme resolution as well as support for upload files. The default handler is a very simple Controller interface, just offering a ModelAndView handle Request(request,response) method. This can already be used for application controllers, but you will prefer the included implementation hierarchy, consisting of, for example AbstractController, AbstractCommandController and SimpleFormController. Application controllers will typically be subclasses  of those.

Spring Web MVC allows you to use any object as a command or form object – there is no need to implement a framework-specific interface or base class. Spring’s data binding is highly flexible: for example, it treats type mismatches as validation errors that can be evaluated by the application, not as system errors. All this means that you don’t need to duplicate your business objects’ properties as simple, untyped strings in your form objects just to be able to handle invalid submissions, or to convert the Strings properly. Instead, it is often preferable to bind directly to your business objects.

Spring’s view resolution is extremely flexible. A Controller implementation can even write a view directly to the response (by returning null for the ModelAndView). In the normal case, a ModelAndView instance consists of a view name and a model Map, which contains bean names and corresponding objects (like a command or form, containing reference data). View name resolution is highly configurable, either via bean names, via a properties file, or via your own ViewResolver implementation. The fact that the model (the M in MVC) is based on the Map interface allows for the complete abstraction of the view technology. Any renderer can be integrated directly, whether JSP, Velocity, or any other rendering technology. The model Map is simply transformed into an appropriate format, such as JSP request attributes or a Velocity template model.

Spring’s web module provides a wealth of unique web support features, including:

  1. Clear separation of roles – controller, validator, command object, form object, model object, DispatcherServlet, handler mapping, view resolver, etc. Each role can be fulfilled by a specialized object.
  2. Powerful and straightforward configuration of both framework and application classes as JavaBeans, including easy referencing across contexts, such as from web controllers to business objects and validators.
  3. Adaptability, non-intrusiveness. Use whatever controller subclass you need (plain, command, form, wizard, multi-action, or a custom one) for a given scenario instead of deriving from a single controller for everything.
  4. Reusable business code – no need for duplication. You can use existing business objects as command or form objects instead of mirroring them in order to extend a particular framework base class.
  5. Customizable binding and validation – type mismatches as application-level validation errors that keep the offending value, localized date and number binding, etc instead of String-only form objects with manual parsing and conversion to business objects.
  6. Customizable handler mapping and view resolution – handler mapping and view resolution strategies range from simple URL-based configuration, to sophisticated, purpose-built resolution strategies. This is more flexible than some web MVC frameworks which mandate a particular technique.
  7. Flexible model transfer – model transfer via a name/value Map supports easy integration with any view technology.
  8. Customizable locale and theme resolution, support for JSPs with or without Spring tag library, support for JSTL, support for Velocity without the need for extra bridges, etc.
  9. A simple yet powerful JSP tag library known as the Spring tag library that provides support for features such as data binding and themes. The custom tags allow for maximum flexibility in terms of markup code. For information on the tag library descriptor, see the appendix entitled Appendix D, spring.tld
  10. A JSP form tag library, introduced in Spring 2.0, that makes writing forms in JSP pages much easier. For information on the tag library descriptor, see the appendix entitled Appendix E, spring-form.tld
  11. Beans whose lifecycle is scoped to the current HTTP request or HTTP Session. This is not a specific feature of Spring MVC itself, but rather of the WebApplicationContext container(s) that Spring MVC uses.

The DispatcherServlet

Spring’s web MVC framework is, like many other web MVC frameworks, request-driven, designed around a central servlet that dispatches requests to controllers and offers other functionality facilitating the development of web applications. Spring’s DispatcherServlet however, does more than just that. It is completely integrated with the Spring IoC container and as such allows you to use every other feature that Spring has.

 


Mathematics, Technology and Programming are my passion. I am a part of Java Ecosystem and through this blog, I contribute to it. I am here to blog about my interests, views and experiences. I am on Google+ and Facebook. I feel proud to be listed as a "National Memory Record Holder" in the Limca Book of Records, 2009 and have attempted for an International Memory record in the Guiness Book of Records. I can remember the value of PI upto 10,000 digits after the decimal (3.1415.....). You can contact me on javagenious.com(At)gmal.com ; I would like to hear from you :)

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