python怎么安装flask

mkproject fvenv --python=/usr/bin/python3

直接进入fvenv目录和虚拟环境中，使用pip安装flask

from flask import Flask

app = Flask(__name__)

@app.route('/')

def hello_world():

    return 'Hello World!'

if __name__ == '__main__':

    app.run()

python3 hello.py