1.initModel

        功能：

public void initModel(NativeWebRequest request, ModelAndViewContainer container, HandlerMethod handlerMethod)
			throws Exception {

		Map<String, ?> sessionAttributes = this.sessionAttributesHandler.retrieveAttributes(request);
		container.mergeAttributes(sessionAttributes);
		invokeModelAttributeMethods(request, container);

		for (String name : findSessionAttributeArguments(handlerMethod)) {
			if (!container.containsAttribute(name)) {
				Object value = this.sessionAttributesHandler.retrieveAttribute(request, name);
				if (value == null) {
					throw new HttpSessionRequiredException("Expected session attribute '" + name + "'", name);
				}
				container.addAttribute(name, value);
			}
		}
	}

2.updateModel