SPRINGMVC controller, processor, Mapper, adapter

Front Controller Dispatcherservlet

<!--define Spring MVC's Front controller servlet--
<servlet>
<!--servlet name--
<servlet-name>SpringMVC</servlet-name>
<!--servlet corresponding Java class--
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--parameter information for the current servlet--
<init-param>
<!--contextconfiglocation is the parameter name, and the value of this parameter contains the SPRINGMVC profile path--
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<!--load servlet--> as soon as the Web App starts
<load-on-startup>1</load-on-startup>
</servlet>


<!--Let Pringmvc's front-end controller intercept all request URLs (not including jsp-->
<!--servlet Mapping declaration --
<!--/means intercept all servlet requests --
<!--/* indicates that all servlet requests are blocked, JSP files--
<servlet-mapping>
<servlet-name>SpringMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>



1) Dispatcherservlet after receiving the request, according to the processor mapping configured in the corresponding configuration file, find the corresponding processor mapping entry (handlermapping), according to the configured mapping rules, find the corresponding processor (Handler). 
2) Call the processing method in the appropriate processor and process the request, and the processor will pass a Modelandview type of data to Dispatcherservlet, which contains the data to be used in the view and view of the processing result. 
3) Dispatcherservlet find a suitable viewresolver (view parser) according to the View object in the resulting modelandview, according to the configuration of the view parser, Dispatcherservlet the view to display the data to the corresponding view, and finally constructs an HTTP response to the browser

1.DisPatcherServlet Front-end controller
Core. The user enters the URL in the browser, initiates the request, first arrives at the Dispatcherservlet, it calls the other component to cooperate the completion of the work, the existence of dispatcherservlet greatly reduces the coupling between the components
2.HandlerMapping Processor Mapper
Record URL and processor mappings in the form of annotations, XML configuration, etc.
3.HandLer processor
Back-end controllers (popular point: The business code written by the controller layer). Processing a user's request
4.HandlerAdapter Processor Adapter
The processor is executed through the Handleradapter, which is an application of the adapter pattern that can be performed on more types of processors through the extension adapter. (I don't understand it too)
5.ViewResolver View Resolver
Viewresolver is responsible for parsing the view and rendering (data filling) to show the results to the user through the page.
6.View View
View is an interface that implements classes that support different view types (JSP, freemarker, Velocity)

SPRINGMVC controller, processor, Mapper, adapter