想在spring mvc 3中为我的登录表单使用会话变量

My Controller:

@Controller
@RequestMapping("/articles")
@SessionAttributes({"user_sess"})
public class ArticleController {
@Autowired
private ArticleService articleService;

@RequestMapping(value = "/save", method = RequestMethod.POST)
public ModelAndView saveArticle(@ModelAttribute(" article ") Article  article,
        BindingResult result) {
        ModelAndView modelAndView = new ModelAndView();

        modelAndView.addObject("user_sess",article.getUser());
        System.out.println("article.getUser()"+article.getUser());
     articleService.addArticle( article);

//                 session.setAttribute("user_Sess", article.getUser()); 
//      return new ModelAndView("redirect:/articles.html");
             return new ModelAndView("Welcome");
}

@RequestMapping(method = RequestMethod.GET)
public ModelAndView listArticles() {
    Map<String, Object> model = new HashMap<String, Object>();
    model.put("articles",  articleService.listArticles());

    return new ModelAndView("articlesList", model);
}

@RequestMapping(value = "/add", method = RequestMethod.GET)
public ModelAndView addArticle(@ModelAttribute("article") Article article,
        BindingResult result) {
    return new ModelAndView("addArticle");
}

}
@Controller
@RequestMapping("/