hello flask

from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello():
    return "hello world"

@app.route('/about')
def about():
    return '这是一个用flask建立的小网站'

@app.route('/user/<username>')
def show_user(username):
    return 'User Name is {}'.format(username)

if __name__ == '__main__':
    app.run()