public String login(){
//		System.out.println("userName = " + this.userName + ", userPassword = " + this.userPassword);
		User user = null;
		try {
			user = this.userServiceImpl.loginUser(new User(this.userName, this.userPassword));
		} catch (Exception e) {
			e.printStackTrace();
		}
		if(user == null){//¼ʧ
			return "loginerror";
		}
		this.session.put("user", user);
		return LOGIN;
	}