controller层中，参数的获取方式以及作用域的问题

 package com.krry.web;

 import javax.servlet.http.HttpServletRequest;

 import org.springframework.stereotype.Controller;
 import org.springframework.ui.ModelMap;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.servlet.ModelAndView;

 import com.fasterxml.jackson.annotation.JsonTypeInfo.Id;

 import bean.User;

 @Controller
 @RequestMapping("/model")
 public class ModelMapController extends BaseController {
     /********参数获取的方式**************************/

     //http://localhost/krryxa/model/hanlder/1.html
     @RequestMapping("/handler/{id}")
     public String handler(@PathVariable("id")Integer id){
     //获得参数id为1
         return "redirect:/success.jsp";
     }

     //http://localhost/krryxa/model/handler2.html?id=5
     @RequestMapping("/handler2")
     public String handler2(Integer id){
     //获得参数id为5
         System.out.println(id);
         return "redirect:/success.jsp";
     }

     //通过对象的的注入方式最好
     //http://localhost/krryxa/model/handler3.html?username=1351
     @RequestMapping("/handler3")
     public String handler3(User user){
     //获得参数username为1351
         System.out.println(user.getUsername());
         return "redirect:/success.jsp";
     }

     //http://localhost/krryxa/model/handler4.html?id=5
     @RequestMapping("/handler4")
     public String handler4(@ModelAttribute("teacher")User user){//若sessiong域中teacher改变了，这里也会改变
     //获得参数id为5
         System.out.println(request.getParameter("id"));
         return "redirect:/success.jsp";
     }

     /**作用域的问题reuqest session application 以下作用域的范围都是:request**/

     //在index页面直接用${message}获取
     @RequestMapping("/handler7")
     public String handler7(ModelMap map){
         //这里是map的addAttribute设置
         map.addAttribute("message", "我爱你吗。你们爱我我吗");
         return "model/index";
     }

     //在index页面直接用${message}获取
     @RequestMapping("/handler5")
     public String handler5(){
         request.setAttribute("message", "我爱你吗。你们爱我我吗");
         return "model/index";
     }

     //在index页面直接用${message}获取
     @RequestMapping("/handler6")
     public ModelAndView handler6(){
         //视图和作用域融合体
         ModelAndView modelAndView = new ModelAndView();
         modelAndView.setViewName("model/index"); //跳转到这个页面
         modelAndView.addObject("message", "是打发是大法师的发送到发士大夫阿什顿");
         return modelAndView;
     }
     //在index页面直接用${user.username}获取
     @RequestMapping("/handler8")
     public String handler8(@ModelAttribute("user")User user){
         user.setUsername("ModelAttribute 我爱你吗。你们爱我吗");
         return "model/index";
     }

 }