项目结构：
app.py
from flask import Flask, render_template
app = Flask(__name__)
@app.route('/')
def hello_world():
url_str = 'https://www.baidu.com'
return render_template('index.html', url_str = url_str)
if __name__ == '__main__':
app.run(host='192.168.235.128', port=5000, debug=True)
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h1>学习</h1>
{
{
url_str }}
</body>
</html>
运行：
运行结果：
