3.springmvc Action向视图传值

一、通过Request.setAttribute("key","vlaue")


@RequestMapping(value="showUserInfo" )
    public String showUserInfo(User user ,   HttpServletRequest req  )
    {


           req.setAttribute("user",user.toString());
        System.out.println(user.toString());
        return "index.jsp";
    }

视图端调用方法 ${user}

二、Model

/***
 *  通过model 方式向视图页面传递值
 * @param model
 * @return
 */
    @RequestMapping("/model")
public  String sentValue(Model model)
{

    model.addAttribute("user","model传值");
    return "index";
}
三、ModelMap

/***
 * 通过ModelMap传值
 * @param mm
 * @return
 */
@RequestMapping("/ModelMap")
public   String ModelMap(ModelMap  mm)
{
    mm.addAttribute("user","ModelMap传值");
    return "index";
}

四、map 传值
/***
 *   map 传值
 * @param map
 * @return
 */
@RequestMapping("/map")
public String map(Map map)
{
    map.put("user" ,"map传值 123");

    return "index";
}
五、ModelView

@RequestMapping("/modelandview")
public ModelAndView  modelandview()
{
    ModelAndView  mv=new ModelAndView("index");// 1.指定视图第一种方式

    mv.setViewName("index" );//或者 通过 setviewName 指定视图第二种方式 
    mv.addobject("user" ,"modelandView 传值 ");
    return mv;
}

六、Session

@RequestMapping("/session")
public  String  session( HttpServletRequest req)
{
    req.getSession().setAttribute("user"," session 传值！！");
    return "index";
}

或

@RequestMapping("/session01")
public  String  session01( HttpSession session)
{
    session.setAttribute("user"," session 传值！！");
    return "index";
}


七，页面调用3种方式 

<textarea> ${user}  <!--  request  session  都可以  -->    </textarea>

<div>
    ${requestScope.user}
</div>

获取session 数据 用

<div>
    ${sessionScope.user}  或者   ${user}
</div>

 八、@SessionAttributes("user") 作用
   主要从model 找 key 为user 的值 并拷贝一份存入session

如：建立HomeController

@SessionAttributes("key")
@Controller
public class HomeController {

    @RequestMapping("/main")
    public  String  main(  Model m)
    {
         
        m.addAttribute("key","计算机");
        return "Home";

    }
}

Home.jsp页面

1 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
2 <html>
3 <head>
4     <title>Title</title>
5 </head>
6 <body>
7    session中 key 值::${sessionScope.key}
8 </body>
9 </html>

结果 session中 key 值:: 计算机

3.springmvc Action向视图传值

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