Spring MVC architecture

Spring MVC architecture

Key components in the Spring MVC architecture are shown in the following figure:


 

Let's look at an example flow and understand the different steps involved in executing the flow. We will take flow 4,

 returning ModelAndView as the specific example. The URL of flow 4 is http://localhost:8080/welcome-model-view. The

 different steps are detailed as follows:

•  The browser issues a request to a specific URL. DispatcherServlet is the Front Controller, handling all requests.

So, it receives the request.

• Dispatcher Servlet looks at the URI (in the example, /welcome-model-view) and needs to identify the right controller  

to handle it. To help find the right controller, it talks to the handler mapping.

• Handler mapping returns the specific handler method (in the example, the welcome method in BasicModelViewController)

   that handles the request.

• DispatcherServlet invokes the specific handler method (public ModelAndView welcome(ModelMap model)).

• The handler method returns the model and view. In this example, the ModelAndView object is returned.

• DispatcherServlet has the logical view name (from ModelAndView; in this example, welcome-model-view). 

It needs to figure out how to determine the physical view name. It checks whether there are 

any view resolvers available. It finds the view resolver that was configured 

(org.springframework.web.servlet.view.InternalResourceViewResolver).

It calls the view resolver, giving it the logical view name (in this example, welcome-model-view) as the input.

• View resolver executes the logic to map the logical view name to the physical view name. 

In this example, welcome-model-view is translated to /WEB-INF/views/welcome-model-view.jsp.

• DispatcherServlet executes the View. It also makes the Model available to the View.

• View returns the content to be sent back to DispatcherServlet.”

• DispatcherServlet sends the response back to the browser.

摘录来自: Ranga Rao Karanam. “Mastering Spring 5.0”。 iBooks.