python：前端（HTML）+后端（Django）+数据库（MySQL）

1、创建一个html文件用于简单的网页注册demo

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>注册</title>
</head>
<body>
<!--表单域，action用于将获取的到信息提交到后台地址-->

<form action="save" method="get">
    <span>
        用户:<input type="text" name="username">
    </span>
    <br>
    <span>
        密码:<input type="password" name="password">
    </span>
    <br>
    <span>
        <input type="submit" name="submit1" value="注册">
    </span>

</form>
</body>
</html>

2、创建一个html文件用于简单的网页登录demo

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录</title>
</head>
<body>
<form action="query" method="get">
    <span>
        用户:<input type="text" name="username">
    </span>
    <br>
    <span>
        密码:<input type="password" name="password">
    </span>
    <br>
    <span>
        <input type="submit" name="submit1" value="登录">
    </span>

</form>
</body>
</html>

3、创建一个Django项目，并将刚才的两个html文件放入template模板文件夹中

4、打开Django项目下默认生成的urls.py文件，进行一些业务功能的编辑

"""Django01 URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path
from django.shortcuts import render
from django.shortcuts import HttpResponse
import pymysql
#登录页面
def login(request):
    #指定要访问的页面，render的功能：讲请求的页面结果提交给客户端
    return render(request,'login.html')
#注册页面
def regiter(request):
    return render(request,'regiter.html')
#定义一个函数，用来保存注册的数据
def save(request):
    has_regiter = 0#用来记录当前账号是否已存在，0：不存在 1：已存在
    a = request.GET#获取get()请求
    #print(a)
    #通过get()请求获取前段提交的数据
    userName = a.get('username')
    passWord = a.get('password')
    #print(userName,passWord)
    #连接数据库
    db = pymysql.connect('127.0.0.1','root','123','db2')
    #创建游标
    cursor = db.cursor()
    #SQL语句
    sql1 = 'select * from user1'
    #执行SQL语句
    cursor.execute(sql1)
    #查询到所有的数据存储到all_users中
    all_users = cursor.fetchall()
    i = 0
    while i < len(all_users):
        if userName in all_users[i]:
            ##表示该账号已经存在
            has_regiter = 1

        i += 1
    if has_regiter == 0:
        # 将用户名与密码插入到数据库中
        sql2 = 'insert into user1(username,password) values(%s,%s)'
        cursor.execute(sql2,(userName,passWord))
        db.commit()
        cursor.close()
        db.close()
        return HttpResponse('注册成功')
    else:

        cursor.close()
        db.close()
        return HttpResponse('该账号已存在')

def query(request):
    a = request.GET
    userName = a.get('username')
    passWord = a.get('password')
    user_tup = (userName,passWord)
    db = pymysql.connect('127.0.0.1','root','123','db2')
    cursor = db.cursor()
    sql = 'select * from user1'
    cursor.execute(sql)
    all_users = cursor.fetchall()
    cursor.close()
    db.close()
    has_user = 0
    i = 0
    while i < len(all_users):
        if user_tup == all_users[i]:
            has_user = 1
        i += 1
    if has_user == 1:
        return HttpResponse('登录成功')
    else:
        return HttpResponse('用户名或密码有误')
urlpatterns = [
    path('admin/', admin.site.urls),#系统默认创建的
    path('login/',login),#用于打开登录页面
    path('regiter/',regiter),#用于打开注册页面
    path('regiter/save',save),#输入用户名密码后交给后台save函数处理
    path('login/query',query)#输入用户名密码后交给后台query函数处理

]