1. 下载BootStrap，然后再Jsp标签中添加如下标签：
<html>
<head lang="zh-cn">
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>签到</title>
<link href="css/bootstrap.min.css" rel="stylesheet">
</head>