public String userLogin(){
		String email = request.getParameter("email");
		String password = request.getParameter("password");
		UserDAO dao = DAOFactory.getUserDAO();
		User user;
		try {
			user = dao.findOneUserByEmail(email);
			if (user.getPassword().equals(password)) {
				request.getSession().setAttribute("user", user);
				//response.sendRedirect("../OpResult.jsp?op=login&ret=true");
				return "success";
			} else {
				//response.sendRedirect("../OpResult.jsp?op=login&ret=false");
				return "fail";
			}
		} catch (Exception e) {
			//response.sendRedirect("../OpResult.jsp?op=login&ret=false");
			return "fail";
		}
	}