<html xmlns:th="http://www.thymeleaf.org"
      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
      layout:decorator="layout/bootstrap4">
<head>
    <meta charset="UTF-8">
</head>
<body>
<div layout:fragment="content">
    <h1 class="page-title text-center py-3">登录</h1>

    <div class="mt-3">
        <form th:action="@{/authenticate}" method="post" class="mx-auto w-50">
            <div class="form-group">
                <label for="exampleInputEmail1">用户名</label>
                <inp