spring MVC 如何获取session并实现传值到前台

后台获取session：

@RequestMapping("/usrlogin")
public ModelAndView usrlogin(@RequestParam String usrid,
      @RequestParam String passwd) {
    HttpSession session = getSession();
    User user = new User();
    user = userMapper.getUserByUsridAndPasswd(usrid, passwd);
    if (null != user) {
      session.setAttribute("user", user.getUser_id());
//            User user1=(User)session.getAttribute("user");
//            System.out.println(user1.getUser_name());

      return new ModelAndView("main");
    } else {
      return new ModelAndView("error");
    }
  }

public static HttpSession getSession() {
  HttpSession session = null;
  try {
    session = getRequest().getSession();
  } catch (Exception e) {}
    return session;
} 

public static HttpServletRequest getRequest() {
  ServletRequestAttributes attrs =(ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
  return attrs.getRequest();
} 

前台jsp取值：

<%
        HttpSession s = request.getSession();
  %>

<span><%=s.getAttribute("user")%></span>

@RequestMapping("/usrlogin")
public ModelAndView usrlogin(@RequestParam String usrid,
@RequestParam String passwd) {
HttpSession session = getSession();
User user = new User();
user = userMapper.getUserByUsridAndPasswd(usrid, passwd);
if (null != user) {
session.setAttribute("user", user.getUser_id());
//			User user1=(User)session.getAttribute("user");//			System.out.println(user1.getUser_name());

return new ModelAndView("main");
} else {
return new ModelAndView("error");
}
}

public static HttpSession getSession() {
HttpSession session = null;
try {
session = getRequest().getSession();
} catch (Exception e) {}
return session;
} 

public static HttpServletRequest getRequest() {
ServletRequestAttributes attrs =(ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
return attrs.getRequest();
}