SpringMVC 之 ModelAndView和ModelAttribute的使用
SpringMVC 之 ModelAndView和ModelAttribute的使用
ModelAndView解释 :
This class merely holds both to make it possible for a controller to return both model and view in a single return value.
这类控制器可以同时返回视图和模型数据.
ModelAndView使用:
ModelAndView()Default constructor for bean-style usage: populating bean properties instead of passing in constructor arguments. |
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ModelAndView(String viewName)Convenient constructor when there is no model data to expose. |
ModelAndView(String viewName,Map<String,?> model)Creates new ModelAndView given a view name and a model. |
ModelAndView(String viewName,String modelName, Object modelObject)Convenient constructor to take a single model object. |
ModelAndView(View view)Convenient constructor when there is no model data to expose. |
ModelAndView(View view,Map<String,?> model)Creates new ModelAndView given a View object and a model. |
ModelAndView(View view,String modelName,Object modelObject)Convenient constructor to take a single model object. |
ModelAttribute的使用:
在方法定义上使用 @ModelAttribute 注解： Spring MVC在调用目标处理方法前，会在每个目标方法前,先逐个调用在方法级上标注了@ModelAttribute 的方法。 在方法的入参前使用 @ModelAttribute 注解：
流程:1.执行@ModelAttribute注解的方法: 从数据库取出相关对象,自动把对象放到request的map中
2.SpringMvc 从map中取出相关对象,并把前台相关的表单属性赋值给这个对象