JavaVM.net

Spring provides a mechanism to intercept the request before it is handled by handler method. Any class can act as an interceptor provided it implements HandlerInceptor interface. This interface has three methods which gets called at different points. Methods in HandlerInceptor Interface preHandle(): This method is invoked before the handler method gets invoked. Return Values

@ModelAttribute annotation is used as part of MVC web flow. This is used for preparing the model data and to define the command object that would be bound with the HTTP request data. This can only work if the class is annotated with @Controller. This annotation can be used on method or on method parameters.

We have seen two most frequently used elements of @RequestMapping annotation. Other which can be used are consumes, produce, params and headers. consumes: This element will consume given content-type specified. produces: This element will produce response of content-type specified. Here is an example. Above handler method will only handle request with specified mapping and content-type.

We have seen in first part how primary mapping can be defined using value element of @RequestMapping. Here we see what other elements do in @RequestMapping annotation. All the other @RequestMapping annotations are used for narrowing down the primary mapping. method Second most important element is method which tells which handler method will get invoked.

As defined in this post what controllers and which is the most important annotation which makes it handle request from client. @RequestMapping annotation comes with number of optional elements which decides the behaviour of a handler method. Following are the elements which can be used with @RequestMapping. S.No. Element Modifier & Type Description 1 value

What are Controllers? Controllers are usually JavaBeans which interprets request. After DispactherServlet receives a request and resolves locale, resource etc it delegates the request to controllers. Controller processes user request and populates model object with result and then represented the same to the user by the view. In some cases it invoke business logic or

As we all know Spring MVC framework is request driven. DispatcherServlet plays a major role in spring MVC framework. In spring MVC its an expression of “Front Controller” design pattern. DispatcherServlet is a simple servlet which gets defined in web.xml DispatcherServlet –> extends –> abstract FrameworkServlet –> extends –> abstract HttpServletBean –> extends –> javax.servlet.http.HttpServlet