1,修改主目录，settings.py文件
DEBUG = False
ALLOWED_HOSTS = ['*',]2,在templates目录下放置404.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<p>该页面不存在。。。</p>
</body>
</html>3， 访问不存在页面的时候就会跳转置404.html
