jsp页面：
<div id="welcome">欢迎<%=session.getAttribute("loginUserNane")%>使用本系统</div>

SuperAction：
public void setServletRequest(HttpServletRequest request) {
        this.request=request;
        this.session=request.getSession();
    }

    UsersAction:
    //用户登录动作
    public String login(){
        UsersDAO udao=new UsersDAOImpl();
        if(udao.usersLogin(user))
        {
            //在session中保存登陆成功的用户名
            session.setAttribute("loginUserName",user.getUsername());
            //request.setAttribute("loginUserName", user.getUsername());
            return "login_success";
            
        }