Springmvc 返回页面数据

一、返回页面数据 ：Model
1. HttpServletRequest request 直接使用 request.setAttribute("user", str);
2. 使用 ModelAndView
3. 使用 Model
4. 使用 Map

@RequestMapping(value="/add1.do")
    public String add(HttpServletRequest request){
        //System.out.println("------ 添加用户信息 ------");
        String name = request.getParameter("username");
        String pass = request.getParameter("password");
        System.out.println("username:" + name + " password: " + pass);
        String str = "username:" + name + " password: " + pass;
        request.setAttribute("user", str);
        return "user_add1";
    }
    
    @RequestMapping(value="/add2.do")
    public ModelAndView add2(){
        
        ModelAndView mav = new ModelAndView();
        mav.addObject("userId",1001);
        mav.addObject("username", "柳岩");
        mav.setViewName("user_add2");       
        return mav;
        
    }
    
    
    @RequestMapping(value="/add3.do")
    public String add3(Model model){
        
        model.addAttribute("userId", 10086);    
        model.addAttribute("username", "柳岩");
        return "user_add3";
        
    }
    
    @RequestMapping(value="/add4.do")
    public String add4(Map map){
        
        
        System.out.println(map.get("username"));
        map.put("userId", 12306);   
        map.put("username", "柳岩");
        return "user_add4";
        
    }