springMVC(servlet)8-11

 springMVC(servlet)
*   跳转
*   view -> Controller
*   1.<bean name="/helloController" class="Controller"></bean>
* 2.
* @Controller("gradeController")
@RequestMapping("/gradeController")
* Controller -> view
* 1. return ModelAndView
* 2. return String
* 传值
* view -> Controller
* @RequestParam()
* 直接入参（参数与表单名称相同）
* Controller -> view
* ModelAndView
* Model
* Map