Spring(Spring MVC):Part two

DispatcherServlet is a core class of Spring MVC.It proccess all request for Spring MVC based application.

Open DispatcherServlet.java,you can learn some core concept fo Spring MVC:

HandlerMapping

HandlerAdapter

ViewResolver

MultipartResolver

LocalResolver

ThemeResolver

All are very important for Spring MVC.And all are configurable.That’s make Spring MVC very flexible.

DispatcherServlet’s initStrategies(ApplicationContext) will init all above core object.

HandlerMapping

HandlerMapping,as it’s name mentioned,it’s used to mapping request to handler.For example,you input a /books/1 in address bar,send the request to the Spring MVC application,how the Spring MVC decide which Controller(Action) to proccess this request,that’s HandlerMapping’s responitity.

Application developer can inherit from this class to customize handler mapping strategy,such as mapping by session or cookie.

There are many implementions by Spring.DefaultAnnotationHandlerMapping(for @RequestMapping),SimpleUrlHandlerMapping,BeanNameUrlHandlerMapping.etc.We will go details later.

HandlerAdapter

HandlerAdapter is an adapter for handler,just a joke.In the privious article,we can see a simple Spring MVC based Controller,it not inherit from any Spring classes,just add some annotation.Why?The interesting thing is in HandlerAdapter.When we find a pure Controller class,we can use HandlerAdapter to wrappe this class.

Adapter is a design pattern,you can refer to GOF’s Design Pattern book.

ViewResolver

Write this code:

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