public String login(@RequestParam("loginname") String loginname, @RequestParam("password") String password, Model model){
        logger.info("登陸名："+loginname + "密碼"+password);
//        到集合中查詢使用者是否存在，此處用來模擬資料庫驗證
        for (User user: userList){
            if (user.getUserName().equals(loginname)
                    &&
 
 user.getPassword().equals(password)){
                model.addAttribute("user",user);
                return "welcome";
            }
        }
        return "loginForm";
    }

login.jsp檔案，id的loginame寫錯 loginname

<h3>登陸頁面</h3>
<br>
    <form action="login" method="post"/>
 

    <table>
        <tr>
            <td><label>登陸名：</label></td>
            <td><input type="text" id="loginname" name="loginname"></td>
        </tr>
        <tr>
            <td><label>密碼：</label></td>
            <td
 
><input type="password" id="password" name="password"></td>
        </tr>
        <tr>
            <td><input id="submit" type="submit" value="登陸"></td>
        </tr>
    </table>
</body>
</html>