The WebApplicationContext is a child context of the ApplicationContext, which will contain middle-tier services such as transactional service layer objects, data sources, and data access objects.
It's a best practice to keep a clear separation between middle-tier services and web-related components.
The XmlWebApplicationContext is used by the DispatcherServlet to model the model the workflow involved with web applications. The DispatcherServlet inspects the WebApplicationContext for declarations of some special beans of some special beans used to execute the workflow. Some of them will have defaults; some of them you will have to provide yourself. Those beans are:
. A handlerMapping is responsible for determining the appropriate controller to dispatch a request to.
. A ViewREsolver is capable of mapping logic view names to actual views, such as a JavaServer page, a Velocity template. to apply to the contents of the model
. A localeREsolver will resolve the locale to use when rendering a view or prforming other language-dependent logic.
. A MultipartResolver provides support for uploading files with HTTP, for instance by using Commons FieldUpload.
. HandlerExceptionResolvers provide support for catching unexpected exceptions and , for example, informing the user by providing a predfefined view displaying information about the exception.
. Controllers provide the interactional logic of your web application and access to collaborators from your middle tier, which provide actual business services, which should be independent of any particular interface type.
. HandlerInterceptors provide the capability to intercept incoming HTTP requests. Interceptors are useful to add additional crosscutting behavior to your web infrastructure, such as security, loggin , and auditing.
WebApplicationContext inherits all functionality of the ApplicationContext. Beyond that, it holds a reference to the ServletContext.