第一种 : 通过ModelAndView

public class ControllerTest1 implements Controller {
   

   public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
   
       //返回一个模型视图对象
       ModelAndView mv = new ModelAndView();
       mv.addObject("msg","ControllerTest1");
       mv.setViewName("test");
       return mv;
  }
}

通过Model

@RequestMapping("/ct2/hello")
public String hello(@RequestParam("username") String name, Model model){
   
   //封装要显示到视图中的数据
   //相当于req.setAttribute("name",name);
   model.addAttribute("msg",name);
   System.out.println(name);
   return "test";
}

通过ModelMap

@RequestMapping("/hello")
public String hello(@RequestParam("username") String name, ModelMap model){
   
   //封装要显示到视图中的数据
   //相当于req.setAttribute("name",name);
   model.addAttribute("name",name);
   System.out.println(name);
   return "hello";
}