What is model ModelMap and ModelAndView?
ModelMap is an extension of Model with the ability to store attributes in a map and chain method calls. ModelAndView is a holder for a model and a view; it allows to return both model and view in one return value.
What is the difference between model and ModelAndView?
3 Answers. Model is an interface while ModelMap is a class. ModelAndView is just a container for both a ModelMap and a view object. It allows a controller to return both as a single value.
When should I use ModelAndView?
I always use the approach where controller methods return ModelAndView . Simply because it tends to make the controller methods a little more terse. The method parameters are now strictly input parameters. And all output related data is contained in the object returned from the method.
What is ModelAndView?
ModelAndView is a holder for both Model and View in the web MVC framework. These two classes are distinct; ModelAndView merely holds both to make it possible for a controller to return both model and view in a single return value. The view is resolved by a ViewResolver object; the model is data stored in a Map .
How do I use ModelAndView?
Method Summary Add an attribute to the model using parameter name generation. Add an attribute to the model. Clear the state of this ModelAndView object. Return the model map.
What is dispatcher servlet?
The DispatcherServlet is an actual Servlet (it inherits from the HttpServlet base class), and as such is declared in the web.xml of your web application. You need to map requests that you want the DispatcherServlet to handle, by using a URL mapping in the same web.xml file.
Can we use @service instead of repository?
According to documentaion @Repository , @Service , @Controller are all synonyms. They all are just specializations of @Component annotation. So, generally, they can be used one instead of other. First reason: any of these annotations make clear the role of your component in the application.
Can we use @component instead of @service in spring?
Spring provides four different types of auto component scan annotations, they are @Component , @Service , @Repository and @Controller . Technically, there is no difference between them, but every auto component scan annotation should be used for a special purpose and within the defined layer.
What is the difference between ResponseEntity and ResponseBody?
ResponseEntity represents an HTTP response, including headers, body, and status. While @ResponseBody puts the return value into the body of the response, ResponseEntity also allows us to add headers and status code.
What happens when the DispatcherServlet tries to render a view for a given ModelAndView?
DispatcherServlet sends view-name from ModelAndView object to view resolver. View-name along with model in ModelAndView is rendered and finally result shown to end-users.
What does ModelAndView return?
Return whether this ModelAndView object is empty as a result of a call to clear() i.e. whether it does not hold any view and does not contain a model. Returns false if any additional state was added to the instance after the call to clear() .
Can we have two dispatcher servlet?
A web application can define any number of DispatcherServlet instances. Each servlet will operate in its own namespace, loading its own application context with mappings, handlers, etc. Only the root application context as loaded by ContextLoaderListener, if any, will be shared.