Flask Foundation: environment setup + configuration + mapping between URL and attempt + redirection + database connection

One o'clock web Learning notes , I hope it helped you .
Study flask Premise ：

• master python Basics
• master html,css Basics

Module installation ：pip install flask

One 、 The first program

from flask import Flask

app = Flask(__name__)


@app.route("/")
def hello():
    return "<p> Hello, Chuanchuan </p>