2021-01-02

SpringMVC执行流程：
  DispatcherServlet中：
  1.doDispatch中：(适配、进入)

                 processedRequest = this.checkMultipart(request);
                      multipartRequestParsed = processedRequest != request;
                      mappedHandler = this.getHandler(processedRequest);
                      if (mappedHandler == null) {
                          this.noHandlerFound(processedRequest, response);
                          return;
   返回modelandview:
   2.mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

   3.解析视图对象：
   4.重定向或转发：
   5.JSP