01.
protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
     HandlerAdapter ha = this.getHandlerAdapter(mappedHandler.getHandler());
      ha = (HandlerAdapter)var2.next();
 }

 02.
  protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
         Iterator var2 = this.handlerAdapters.iterator();

         HandlerAdapter ha;
         do {
             if (!var2.hasNext()) {
                 throw new ServletException("No adapter for handler [" + handler + "]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler");
             }

             ha = (HandlerAdapter)var2.next();
             if (this.logger.isTraceEnabled()) {
                 this.logger.trace("Testing handler adapter [" + ha + "]");
             }
         } while(!ha.supports(handler));

         return ha;
     }

     03.
     mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
      public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
             return ((Controller)handler).handleRequest(request, response);
         }

     04.自定義的Controller

SpringMVC之HandlerAdapter執行流程