Spring MVC请求流程

request-------->DispatcherServler(中央调度器/前端控制器)----->

HandlerMapping(处理器映射器)------>返回一个执行链----->将执行链转交给HandlerAdaptor(处理器适配器)----->调度Handler(处理器)----->

ModelAndView----->先将结果交给HandlerAdaptor，然后再由HandlerAdaptor转交给 DispatcherServler--------->DispatcherServler调度ViewResolver（视图解析器）---->交给DispatcherServler------->

寻找View---->View做出响应(response)

HandlerMapping执行过程

   

1.在web.xml中寻址前端控制器DispatcherServlet方法doDispatch()

2.HandlerExecutionChainmappedHandler=  getHandler(request)

3.控制权从前端控制器转交给了HandlerMapping出现HandlerMapping hm  getHandler(request)

4.hm.getHanlder()方法使HandlerMapping接口的。我们找到了接口的实现类。AbstractHandlerMapping。

 return this.getHandlerExecutionChain(handler,request);

5.HandlerExecutionChainchain = handler instanceofHandlerExecutionChain?(HandlerExecutionChain)handler:newHandlerExecutionChain(handler);

chain.addInterceptor(mappedInterceptor.getInterceptor());