Django Web开发基础知识

本文章只是学习笔记，部分资料参考自互联网，图片非原创，仅用于学习理解！

MVC 与 MTV

MVC - Model View Controller，模型(model)－视图(view)－控制器(controller)的缩写，是软件工程中的一种软件架构模式，Model模型中主要用于存储与数据库相关的字段或数据库通信方面的东西，Controller控制器用于存储URL的分发等，最后的View视图则是完善控制器中的路径分发，每一个路径对应一个view视图函数。

模型(M)，控制器(C)和视图(V)三层，他们之间以一种插件式的、松耦合的方式连接在一起:

A.模型负责业务对象与数据库的映射(ORM) B.视图负责与用户的交互(页面) C.控制器接受用户的输入调用模型和视图完成用户的请求

ORM：对象关系映射（Object Relational Mapping，简称ORM，或O/RM，或O/R mapping)

通常情况下我们写代码用的是面向对象的方法，而我们的数据库无法支持面向对象的编程，为了解决两者之间的不同，就出现了ORM映射技术，使用这种技术我们无需关注sql语句的具体编写，只需要使用特定的API即可完成复杂的查询删除等任务，但有一个缺点，采用此技术在一定程度上会消耗系统部分资源，而对于非常复杂的查询工作，还是要使用纯SQL语句来写。

Django的MTV模式本质上和MVC是一样的，也是为了各组件间保持松耦合关系，只是定义上有些许不同，Django的MTV分别是值：

M 代表模型（Model）：负责业务对象和数据库的关系映射(ORM)。 T 代表模板 (Template)：负责如何把页面展示给用户(html)。 V 代表视图（View）：负责业务逻辑，并在适当时候调用Model和Template。

除了以上三层之外，还需要一个URL分发器，它的作用是将一个个URL的页面请求分发给不同的View处理，View再调用相应的Model和Template，MTV的响应模式如下所示：

这种设计模式优势在于各组件都是松耦合的。每个由Django驱动的Web应用都有着明确的目的，并且可独立更改而不影响到其它的部分。

HTTP协议：Hyper Text Transfer Protocol（超文本传输协议），是用于万维网服务器与本地浏览器之间传输超文本的传送协议。

该协议是基于TCP/IP的请求协议

HTTP协议规定,请求从客户端发出,最后服务器端响应该请求并返回。换句话说,肯定是先从客户端开始建立通信的,服务器端在没有接收到请求之前不会发送响应无状态保存

HTTP是一种不保存状态,即无状态(stateless)协议。HTTP协议自身不对请求和响应之间的通信状态进行保存,协议对于发送过的请求或响应都不做持久化处理。

无连接:无连接的含义是限制每次连接只处理一个请求。服务器处理完客户的请求，并收到客户的应答后，即断开连接。采用这种方式可以节省传输时间。

HTTP请求方式

GET提交的数据会放在URL之后，以?分割URL和传输数据，参数之间以&相连，POST方法是把提交的数据放在HTTP包的Body中. GET提交的数据大小有限制（因为浏览器对URL的长度有限制），而POST方法提交的数据没有限制. GET与POST请求在服务端获取请求数据方式不同。 GET方式提交数据，会带来安全问题，而POST请求则相对安全。

创建第一个django项目

1.如果是使用Pycharm创建的项目,直接创建项目，即可。

2.如果没有创建app的名字，也可以在进入django目录中，执行 python manage.py startapp MyWeb 命令创建.

更多django shell命令行参数。

 
python manage.py shell     #进入django shell
python manage.py dbshell   #进入django dbshell
python manage.py check     #检查django项目完整性
python manage.py flush     #清空数据库
python manage.py compilemessages   #编译语言文件
python manage.py makemessages      #创建语言文件
python manage.py showmigrations    #查看生成的数据库同步脚本
python manage.py sqlflush          #查看生成清空数据库的脚本
python manage.py sqlmigrate        #查看数据库同步的sql语句
python manage.py dumpdata          #导出数据
python manage.py loaddata          #导入数据
python manage.py diffsettings      #查看你的配置和django默认配置的不同之处

2.修改settings.py 配置文件,导入我们的app的名字，去掉csrf这个选项

 
MIDDLEWARE = [
'django.middleware.csrf.CsrfViewMiddleware',  # 为了能够开心玩耍,把这个干掉
]
 
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'MyWeb.apps.MywebConfig'           # 导入
]

3.来urls.py里面写一条路由，名字就叫hello , 映射到views.hello函数下处理此请求。

 
from MyWeb import views       # 导入
 
urlpatterns = [
    path('admin/', admin.site.urls),
    path('hello/',views.hello)
]

4.最后在myweb里面的views.py设置一个视图函数,最后运行。

 
from django.shortcuts import HttpResponse
 
# Create your views here.
# 这个request必须加,不然会报错
def hello(request):
    return HttpResponse("<h1>hello lyshark</h1>")

5.配置好以后，启动django,访问 http://127.0.0.1:8000/ 完成了。

6.如果需要引入静态资源，需要设置一下settings.py

 
# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.0/howto/static-files/
# 这个路径是对应 src="/static/ 的别名
# 如果这个路径改为 STATIC_URL = '/abc/' 那么<script src="/abc/xxx.js"></script>
STATIC_URL = '/static/'
STATICFILES_DIRS = (
    os.path.join(BASE_DIR,'static'),
)

Django 初始化操作

初始化Django:

 
D:\> pip install django                              # 安装
D:\> django-admin startproject MyProject             # 创建项目
D:\MyProject> django-admin startapp MyWeb            # 创建APP
D:\MyProject> python manage.py runserver 0.0.0.0:80  # 启动Django
 
D:\MyProject> python manage.py shell   # 进入Django交互shell
D:\MyProject> python manage.py dbshell # 进入DBShell
D:\MyProject> python manage.py check   # 检查Django完整性

修改一下django的配置文件settings.py,导入我们生成APP的名字.

 
MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    #'django.middleware.csrf.CsrfViewMiddleware',                # 注释掉此行
    'django.contrib.auth.middleware.AuthenticationMiddleware',
]
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'MyWeb.apps.MywebConfig'           # 添加此行,导入我们的APP的名字
]

然会修改urls.py在这里写一条路由记录.

 
from MyWeb import views
 
urlpatterns = [
    path('admin/', admin.site.urls),
    path("hello/",views.hello,name="hello")
]

最后我们在views.py视图函数里添加一条路由.

 
from django.shortcuts import HttpResponse
 
def hello(request):
    return HttpResponse("<h1>hello lyshark</h1>")

有时候我们需要在本地引入JS或者静态资源,此时你需要修改一下Django的setting.py里面的路径.

 
# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.0/howto/static-files/
# 此时我们的默认路径是/static/,那么前端就可以直接调用<script src="/static/lyshark.js">
STATIC_URL = '/static/'
STATICFILES_DIRS=(
    os.path.join(BASE_DIR,'static')
)

Django 模板与视图

简单的路由编写:

 
urlpatterns = [
    path('admin/', admin.site.urls),
    path('',views.index,name="index"),                                     # 一条访问主站的路由
    path('login/id=<int:id>&name=<str:name>',views.login,name="login"),    # 名称后面传递参数
    path('add/<int:x>/<int:y>/',views.add,name="add")                      # 路径中传递参数
]
 
from django.shortcuts import render,HttpResponse
def index(request):
    return render(request,"index.html")
 
def login(request, id, name):
    return HttpResponse("用户ID{} , 用户名{} ".format(id,name))
 
def add(request,x,y):
    temp = int(x)+int(y)
    return HttpResponse("相加结果:{}".format(temp))

使用模板传递简单的参数:

 
**用户名: {{ user }} 密码:{{ pasd }} 标题:{{ title }}:**
 
def index(request):
    username = "lyshark"
    password = "123123"
    title = "hello lyshark"
    return render(request,"index.html",{"user":username,"pasd":password,"title":title})

后端组装数据然后传递给前端:

 
**用户名: {{ user }} 密码:{{ pasd }} 标题:{{ title }}:**
 
def index(request):
    username = "admin"
    password = "123123"
    title = "hello lyshark"
 
    dict = {
        "user": username,
        "pasd": password,
        "title": title
    }
    return render(request,"index.html",dict)

通过info变量遍历出指定字段元素:

 
**站点名称:{{ info.site }} 站点描述:{{ info.content }}:**
 
def index(request):
    info = {"site":"blib.cn","content":"hello lyshark"}
    return render(request,"index.html",{"info":info})

通过for语句遍历打印列表数据:

 
    {% for item in total %}
        **打印数据: {{ item }}:**<br>
    {% endfor %}
 
def index(request):
    lists = ["HTML","CSS","JAVASCRIPT","Python","JQuery"]
    return render(request,"index.html",{"total":lists})

通过for语句倒序循环打印:

 
    {% for item in total reversed%}
        **打印数据: {{ item }}:**<br>
    {% endfor %}
 
def index(request):
    lists = ["1","2","3","4","5"]
    return render(request,"index.html",{"total":lists})

通过使用for循环遍历字典:

 
{% for key,value in info.items %}
    {{ key }} : {{ value }}
{% endfor %}
 
def index(request):
    info = {"site":"blib.cn","content":"hello lyshark"}
    info1 = {"site": "blib.cn", "content": "hello admin"}
 
    return render(request,"index.html",{"info":info,"info1":info1})

简单的路径拼接:

 
<a href="{{ request.path }}?uid=1">当前网址加参数</a>
 
<!--获取当前路径      拼接成 /add/4/5-->
{{ request.path }}{% url 'add' 4 5 %}
 
def add(request,x,y):
    temp = int(x)+int(y)
    return HttpResponse("相加结果:{}".format(temp))
 
def index(request):
    return render(request,"index.html")

判断用户是否登录:

 
{% if request.user.is_authenticated %}
    {{ request.user.username }}，您好！
{% else %}
    请登陆，这里放登陆链接
{% endif %}

使用if语句判断数据:

 
{% if username == "lyshark" and password == "123123" %}
    **恭喜你:**
{% elif username == "admin" or password == "123123" %}
    **欢迎管理员:**
{% else %}
    **这个都不是:**
{% endif %}
 
def index(request):
    username = "admin"
    password = "123123"
    return render(request,"index.html",{"username":username,"password":password})

if语句也可以判断列表元素:

 
{% if 1 in list %}
    **在里面:**
{% elif 10 not in list %}
    ** 不在里面:**
{% endif %}
 
def index(request):
    list = [1,2,3,4,5]
    return render(request,"index.html",{"list":list})

最后的大总结:if与for语句的结合:

 
{% for item in info %}
    {% if forloop.first %}
        **开始了:**
    {% endif %}
    {{ forloop.counter }} : {{ item }}<br>
    {% if forloop.last %}
        **最后了:**
    {% endif %}
{% endfor %}
 
def index(request):
    list = map(str,range(100))
    return render(request,"index.html",{"info":list})
 
forloop.counter 索引从 1 开始算
forloop.counter0    索引从 0 开始算
forloop.revcounter  索引从最大长度到 1
forloop.revcounter0 索引从最大长度到 0
forloop.first   当遍历的元素为第一项时为真
forloop.last    当遍历的元素为最后一项时为真
forloop.parentloop  
用在嵌套的 for 循环中，获取上一层 for 循环的 forloop

常用的过滤器:: 常用的过滤器,有以下几种.

 
    ** 列表长度: {{ total | length }}:**<br>
    ** 输出大小: {{ size | filesizeformat }}:**<br>
    ** 输出时间: {{ date | date:"Y-m-d" }}:**<br>
    ** 首字母大写: {{ title | capfirst }}:**<br>
    ** 从字符串中移除hello字符: {{title | cut:"hello" }}:**<br>
    ** 显示字符串第一个元素: {{ total | first }}:**<br>
    ** 显示字符串最后一个元素: {{ total | last }}:**<br>
    ** 大小写转换(upper/lower): {{ title | upper }}:**<br>
    ** 对数据切片: {{ title | slice:"2:-1" }}:**<br>
    **截断字符：{{ title | truncatechars:5 }}:**<br>
    **截断单词：{{ title | truncatewords:1 }}:**
 
def index(request):
    filesize = 10240
    title = "hello lyshark"
    date = datetime.datetime.now()
    lists = ["1","2","3","4","5"]
    return render(request,"index.html",{"total":lists,"size":filesize,"date":date,"title":title})

自定义过滤器与标签:

1.首先在Django项目下的APP里面,创建一个templatetags的目录,这个目录名不能变.

 
MyWeb/
    __init__.py
    models.py
    templatetags/
        __init__.py
        mysimple.py
    views.py

2.在templatetags目录下创建任意的py文件,此处我们就创建一个mysimple.py,并写入以下两条内容.

 
from django import template
from django.utils.safestring import mark_safe
 
register = template.Library() # 此处必须这样写
 
# simple_tag（自定义标签）：不会限制传参,但不支持if
@register.simple_tag
def simple_time(var1,var2,var3):
    temp = int(var1)+int(var2)+int(var3)
    return temp
 
# filter（自定义过滤器）：限制传参2个,但支持if
@register.filter
def My_filter(value, arg):
    # 传递一个参数的过滤器
    return str.upper(value) + arg

3.在我们需要使用自定义过滤器的时候,必须在index.html中引入这个变量,然后在前端就可以调用了.

 
# name: views.py
def index(request):
    title = "hello"
    return render(request,"index.html",{"title":title})
 
# name: index.html
<!--引入自定义的过滤器-->
{% load mysimple %}
 
**自定义标签返回数值: {% simple_time 10 20 30 %}:**          <!-- 传递多个参数 -->
**传递一个参数的过滤器: {{ title | My_filter:'lyshark' }}:** <!-- 传递一个参数 -->

模板与模板继承:

 
母板：             {% block title %}{% endblock %}
子板继承：         {% extends "base.html" %}
子板中使用其他模板: {% include "xx.html" %}
设置标题:          {% block title %}{% endblock %}
使用CSS资源:       {% block css %} {% endblock %}
使用JS资源:        {% block js %} {% endblock %}

1.首先创建一个base.html文件,以作为我们的母版.

 
<html>
<head>
    <meta charset="UTF-8">
    {% block css %}{% endblock %}
</head>
    <body>
        <div class="pg-body">
            <div class="body-menu">
                <ul>
                    <li><a href="/user">用户管理</a></li>
                    <li><a href="/hosts">资产管理</a></li>
                </ul>
            </div>
            <div class="body-content">
                {% block body %}{% endblock %}   <!--占位符,用于填充子版块-->
            </div>
        </div>
        {% block js %}{% endblock %}
    </body>
</html>

接着我们需要创建一个子板并继承母版,此处我们创建一个hosts.html这样的文件.

 
{% extends 'base.html' %}
{% block js %} {% endblock %}
{% block css %} {% endblock %}
 
{% block body %}
    <table>
        {% for item in host %}
            <tr>
                <td>{{ item.hostname }}</td>
                <td>{{ item.port }}</td>
            </tr>
        {% endfor %}
    </table>
{% endblock %}

我们继续创建一个user.html,同样也是继承base.html模板.

 
{% extends 'base.html' %}
 
{% block js %} {% endblock %}
{% block css %} {% endblock %}
 
{% block body %}
    <ul>
    {% for item in user_list %}
        <li>{{ item.username }},{{ item.salary }}</li>
    {% endfor %}
    </ul>
{% endblock %}

此处我们需要在urls.py里面写好路由分发.

 
from django.contrib import admin
from django.urls import path
from MyWeb import views
 
urlpatterns = [
    path('admin/', admin.site.urls),
    path('',views.index,name="index"),
    path('hosts/',views.hosts,name="hosts"),
    path('user/',views.userinfo,name="user")
]

然后写好views.py中的视图函数,默认我们返回base.html这个页面.

 
from django.shortcuts import render
from django.shortcuts import HttpResponse
 
def index(request):
    return render(request,"base.html")
 
def hosts(request):
    hosts_list = []
    for i in range(10):
        temp = {'hostname':'192.168.1.'+str(i),'port':80}
        hosts_list.append(temp)
    return render(request,'hosts.html',{'host':hosts_list})
 
def userinfo(request):
    user_list = []
    for i in range(10):
        temp = {'username': 'user' + str(i),'salary':80}
        user_list.append(temp)
    return render(request,'user.html',{'user_list':user_list})

简单的用户登录:

 
# name:login.html
<!DOCTYPE html>
<body lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
    <form action="{% url 'login' %}" method="post">  # 通过模板获取到login的试图
        <input type="text" name="username" />
        <input type="text" name="password" />
        <input type="submit" name="提交"/>
    </form>
</body>
</html>
 
# name: urls.py
from django.contrib import admin
from django.urls import path
from MyWeb import views
 
urlpatterns = [
    path('admin/', admin.site.urls),
    path('login/', views.login, name="login")  # name是给视图起一个名字
]
 
# name:views.py
from django.shortcuts import render,HttpResponse
 
def login(request):
    if request.method == "GET":
        return render(request,"index.html")
    elif request.method == "POST":
        username = request.POST.get("username")
        password = request.POST.get("password")
        return HttpResponse("您提交的用户:{} 密码:{}".format(username,password))

Django 表单操作

普通Form表单的提交:

 
<!-- name:index.html -->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/" method="post">
        <p>账号:<input type="text" name="username"><span>{{ error.username }}</span></p>
        <p>密码:<input type="password" name="password"><span>{{ error.password }}</span></p>
        <input type="submit" value="提交请求">
    </form>
</body>
</html>
# name: views.py
from django.shortcuts import render,HttpResponse
 
def index(request):
    if request.method == "GET":
        return render(request,"index.html")
    else:
        username = request.POST.get("username")
        password = request.POST.get("password")
        error = {"username":"","password":""}
        if len(username) > 10:
            error["username"]="用户名不能大于10"
        if len(password) < 5:
            error["password"] = "密码不能小于5"
        return render(request,"index.html",{"error":error})

实现单项选择框:

 
<form action="/index/" method="post">
 
    选择A:
 
    <select name="tag_select_a">
 
        {% for item in total_a %}
 
            <option value = "{{ item }}"> {{ item }} </option>
 
        {% endfor %}
    </select>
    选择B:
    <select name="tag_select_b">
        {% for item in total_b %}
            <option value = "{{ item }}"> {{ item }} </option>
        {% endfor %}
    </select>
    <input type="submit" value="提交选择">
</form>
def index(request):
    if request.method == "GET":
        tag_select_a = ["HTML", "CSS", "JAVASCRIPT", "Python", "JQuery"]
        tag_select_b = ["MySQL","Oracle","MSSQL"]
        return render(request, "index.html", {"total_a": tag_select_a,"total_b": tag_select_b})
    elif request.method == "POST":
        select_a = request.POST.get("tag_select_a")
        select_b = request.POST.get("tag_select_b")
        return HttpResponse("选择A: {} 选择B: {}".format(select_a,select_b))<b>普通Form表单的提交</b>

提交账号密码:

 
<!-- name:index.html -->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/" method="post">
        <p>账号:<input type="text" name="username"><span>{{ error.username }}</span></p>
        <p>密码:<input type="password" name="password"><span>{{ error.password }}</span></p>
        <input type="submit" value="提交请求">
    </form>
</body>
</html>
# name: views.py
from django.shortcuts import render,HttpResponse
 
def index(request):
    if request.method == "GET":
        return render(request,"index.html")
    else:
        username = request.POST.get("username")
        password = request.POST.get("password")
        error = {"username":"","password":""}
        if len(username) > 10:
            error["username"]="用户名不能大于10"
        if len(password) < 5:
            error["password"] = "密码不能小于5"
        return render(request,"index.html",{"error":error})

Form实现登录表单:

 
<!--name:index.html-->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/" method="post" novalidate>
        <p>账号: {{ form.username }} {{ form.username.errors.0 }}</p>
        <p>密码: {{ form.password }} {{ form.errors.password }}</p>
        <p>重复: {{ form.RepeatPass }} {{ form.errors.RepeatPass }}</p>
        <input type="submit" value="提交">
    </form>
</body>
</html>
# name:views.py
from django.shortcuts import render,HttpResponse
from django.forms import Form,fields,widgets
from django.core.exceptions import ValidationError
 
class LoginForm(Form):
    username = fields.CharField(
        required = True,
        max_length = 10,
        error_messages={"required":"该字段不能为空"},
        widget=widgets.TextInput(attrs={"placeholder":"请输入用户名","class":"form-control"})
    )
    password = fields.CharField(
        required = True,
        max_length=10,
        error_messages={"required":"密码字段不能为空","min_length":"密码最小长度为5"},
        widget=widgets.PasswordInput(attrs={"placeholder":"请输入密码","class":"form-control"})
    )
    RepeatPass = fields.CharField(
        required=True,
        max_length=10,
        error_messages={"required":"密码字段不能为空","min_length":"密码最小长度为5"},
        widget=widgets.PasswordInput(attrs={"placeholder":"重复输入密码","class":"form-control"})
    )
 
    # 自定义方法（局部钩子）密码必须包含字母和数字
    def clean_password(self):
        if self.cleaned_data.get("password").isdigit() or self.cleaned_data.get("password").isalpha():
            raise ValidationError("密码必须包含数字和字母")
        else:
            return self.cleaned_data["password"]
    # 自定义方法（全局钩子, 检验两个字段），检验两次密码是否一致
    def clean_RepeatPass(self):
        if self.cleaned_data.get("password") != self.cleaned_data.get("RepeatPass"):
            raise ValidationError("两次输入密码不正确")
        else:
            return self.cleaned_data
 
def index(request):
    if request.method =="GET":
        form = LoginForm()
        return render(request, "index.html", {"form": form})
    else:
        form = LoginForm(request.POST)
        if form.is_valid():
            # username = form.data['username']
            data = form.cleaned_data
            username = data.get("username")
            password = data.get("password")
            print(username,password)
            return render(request, "index.html", {"form": form})
    return render(request, "index.html", {"form": form})

其他常用Form表单:

 
<!--name: index.html-->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/" method="post">
        {% for field in form %}
            <p>{{ field.label_tag }} {{ field }} {{ field.errors.0 }}</p>
        {% endfor %}
        <input type="submit" value="提交" />
    </form>
</body>
</html>
# name: views.py
from django.shortcuts import render,HttpResponse
from django.forms import Form,fields,widgets
 
class MyForm(Form):
    hobby = fields.ChoiceField(
        label="单选框:",
        required=True,
        initial=1,                # 默认选择1号
        choices=( (1,"篮球"),(2,"足球"),(3,"乒乓球"),(4,"滚球")),
        widget=widgets.RadioSelect()
    )
    select = fields.ChoiceField(
        label="单选框(默认):",
        required=True,
        initial=1,
        choices=( (1,"篮球"),(2,"足球"),(3,"乒乓球"),(4,"滚球")),
        widget=widgets.Select()
    )
    multiple = fields.MultipleChoiceField(
        label="复选框",
        choices=((1, "篮球"), (2, "足球"), (3, "羽毛球"), (4, "排球")),
        initial=[2, 4],
        widget=widgets.SelectMultiple()
    )
    checkbox = fields.ChoiceField(
        label="单项复选框",
        initial="checked",  # 默认为勾选
        widget=widgets.CheckboxInput()
    )
    multselect = fields.MultipleChoiceField(
        label="多项复选框",
        choices=((1, "篮球"), (2, "足球"), (3, "羽毛球"), (4, "排球")),
        initial=[1, 3],
        widget=widgets.CheckboxSelectMultiple()
    )
    data = fields.DateField(
        label="选择日期",
        widget = widgets.DateInput(attrs={"type":"date"})
    )
def index(request):
    if request.method=="GET":
        form = MyForm()
        return render(request,"index.html",{"form":form})
    else:
        form = MyForm(request.POST)
        if form.is_valid():
            data = form.cleaned_data
            print(data.get("hobby"))
    return HttpResponse("hello lyshark")

Form实现用户注册:

 
<!--name: index.html-->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div>
        <form action="/" method="post">
            <p>{{ form.username.label }} {{ form.username }}</p>
            <p>{{ form.password.label }} {{ form.password }}</p>
            <p>{{ form.mobile.label }} {{ form.mobile }} </p>
            <p>{{ form.email.label }} {{ form.email }} </p>
            <p>{{ form.text }} </p>
            <p><input type="submit" value="提交请求"></p>
        </form>
    </div>
</body>
</html>
# name: models.py
from django.db import models
 
class User(models.Model):
    id = models.AutoField(primary_key=True)
    username = models.CharField(max_length=64)
    password = models.CharField(max_length=32)
    mobile = models.CharField(max_length=32)
    email = models.EmailField(max_length=64)
    text = models.CharField(max_length=128)
# name: views.py
from django.shortcuts import render,HttpResponse
from MyWeb import models
from django.forms import Form,fields,widgets
from django.core.validators import RegexValidator
from django.core.exceptions import ValidationError
 
class UserForm(Form):
    username = fields.CharField(
        label = "账号: ",          # 给表单加一个标签
        required = True,           # 不允许字段为空值
        min_length=4,              # 设置最小长度
        max_length = 10,           # 设置最大长度
        validators=[ RegexValidator(r'^[0-9a-zA-Z]+$',"用户账号只能使用,0-9a-z") ],
        error_messages={"required":"该字段不能为空","invalid":"无效的用户名",
                        "min_length":"最小长度为5","max_length":"最大长度为10"},
        widget=widgets.TextInput(attrs={"placeholder":"请输入用户名","class":"form-control"})
    )
    password = fields.CharField(
        label = "密码: ",
        required = True,
        min_length=5,
        max_length=10,
        error_messages={"required":"密码字段不能为空","min_length":"密码最小长度为5"},
        widget=widgets.PasswordInput(attrs={"placeholder":"请输入密码","class":"form-control"})
    )
    mobile = fields.CharField(
        label = "手机: ",
        required=True,
        validators=[RegexValidator('[0-9]', "手机号必须是数字")],
        error_messages={"required":"该字段不能为空"},
        widget=widgets.TextInput(attrs={"placeholder": "手机号","class": "form-control"})
    )
    email = fields.EmailField(
        label="邮箱: ",
        required=True,
        error_messages={"required":"邮箱不能为空！！","invalid":"无效的邮箱"},
        widget=widgets.EmailInput(attrs={"placeholder": "邮箱", "class": "form-control"})
    )
    text = fields.CharField(
        required=True,
        widget=widgets.Textarea(attrs={"placeholder": "畅言,欢迎留言...", "class": "form-control",
                                       "style":"margin: 0px; width: 203px; height: 98px;"})
    )
 
def index(request):
    if request.method =="GET":
        form = UserForm()
        return render(request, "index.html", {"form": form})
    else:
        form = UserForm(request.POST)
        if form.is_valid():
            # username = form.data['username']
            data = form.cleaned_data
            username = data.get("username")
 
            is_exits = models.User.objects.filter(username="admin").count()
            if is_exits != 0:
                return HttpResponse("您注册的用户已存在")
            else:
                models.User.objects.create(**data)
                return HttpResponse("恭喜您的账号注册完成了")
        else:
            return render(request, "index.html", {"form": form.errors})
    return render(request, "index.html", {"form": form})

实现用户验证:

index.html

 
<head>
    <meta charset="UTF-8">
    <script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
</head>
<body>
 
<form action="/" method="post">
    <p> {{ form.email }}</p>
    <p> {{ form.code }} <a id="fetch_code" class="fetch-code" href="javascript:void(0);">获取验证码</a></p>
    <input type="submit" value="提交">
</form>
 
 
<script type="text/javascript">
    $("#fetch_code").click(function(){
        var email = $("#email").val();        // 获取到用户邮箱
        if(email.trim().length != 0)
        {
            $("#fetch_code").empty();
            $("#fetch_code").text("发送成功");
            $.ajax({
                url:"/send_msg/",
                type:"POST",
                data:{email:email},
                dataType:"json",
                success:function(recv){
                }
            })
        }
    })
 
</script>

models.py

 
from django.db import models
 
class SendMsg(models.Model):
    id = models.AutoField(primary_key=True)
    code = models.CharField(max_length=6)
    email = models.CharField(max_length=32, db_index=True)
    count = models.IntegerField(default=0)
    times = models.IntegerField(default=0)
 
class UserInfo(models.Model):
    id = models.AutoField(primary_key=True)
    username = models.CharField(max_length=32, unique=True)
    password = models.CharField(max_length=32)
    email = models.CharField(max_length=32, unique=True)

views.py

 
from django.shortcuts import render,HttpResponse
from django.core.mail import send_mail, send_mass_mail, EmailMultiAlternatives
import re,time,random
from MyWeb import models
 
def SendMail(rand,user):
    title = "本次注册验证码是: {} 十分钟以内有效.".format(rand)
    ret = send_mail("Django 邮件通知",title,"smtpwho@163.com",[user])
    if ret:
        return 1
    return 0
def send_msg(request):
    if request.method=="POST":
        email = request.POST.get("email")
        ret = re.match(r'^[0-9a-zA-Z\_\-]+(\.[0-9a-zA-Z\_\-]+)*@[0-9a-zA-Z]+(\.[0-9a-zA-Z]+){1,}$', email)
        if ret == None:
            print("不合法")
        else:
            ret = models.UserInfo.objects.filter(email=email).count()
            if ret == 1:
                print("你的邮箱已经注册了,请换一个..")
            else:
                ret = models.SendMsg.objects.filter(email=email).count()    # 查询出如果存在sendmsg表里,则不能让其注册
                if ret !=0:
                    print("等待超时,暂时不嫩注册..")
                    times = int(time.time())
                    if times >=models.SendMsg.objects.filter(email=email).values("times"):
                        print(times)
                    else:
                        print("时间还没到")
 
                else:
                    rand = random.randint(10000,20000)
                    if SendMail(rand,email):
                        times = int(time.time()+60)  # 一分钟只能注册一次
                        models.SendMsg.objects.create(email=email,code=rand,times=times)
    return render(request,"reg.html")
 
def reg(request):
    if request.method == "POST":
        email = request.POST.get("email")
        code = request.POST.get("code")
        ret = models.SendMsg.objects.filter(email=email).values("email","code")[0]
        if ret['email']==email and ret['code']==code:
            print("正确了")
            username = request.POST.get("username")
            password = request.POST.get("password")
            ret = models.UserInfo.objects.filter(username=username).count()
            if ret == 0:
                # 等于0说明没有这个用户,可以注册
                models.UserInfo.objects.create(username=username,password=password,email=email)
                print("注册完成了")
            else:
                print("这个账号重复了,请换一个...")
        else:
            print("验证码错误")
    return render(request, "reg.html")

urls.py

 
from django.contrib import admin
from django.urls import path
from MyWeb import views
urlpatterns = [
    path('admin/', admin.site.urls),
    path("reg/",views.reg),
    path("send_msg/",views.send_msg)
]

settings.py

 
STATIC_URL = '/static/'
EMAIL_USER_TLS = True
EMAIL_PORT = 25
EMAIL_HOST = "smtp.163.com"
EMAIL_HOST_USER = "smtpwho@163.com"
EMAIL_HOST_PASSWORD = "123456789"

重写父类方法: 通过form表单重写init方法,实现数据库动态添加,前端动态显示,以两个选择框为例

 
# name: models.py
from django.db import models
 
class DBHost(models.Model):
    id = models.AutoField(primary_key=True)
    host = models.CharField(max_length=32)
    title = models.CharField(max_length=32)
 
# name:index.html
{{ form.title }}
{{ form.host }}
# name:views.py
from django.shortcuts import render
from django.forms import Form,fields,widgets
from MyWeb import models
 
class DBHost(Form):
    title = fields.IntegerField(widget=widgets.Select(choices=[]))
    host = fields.IntegerField(widget=widgets.SelectMultiple(choices=[]))
 
    # 重写父类的 __init__ 方法
    def __init__(self,*args,**kwargs):
        super(DBHost, self).__init__(*args,**kwargs)
        self.fields['title'].widget.choices = models.DBHost.objects.all().values_list("id","title")
        self.fields['host'].widget.choices = models.DBHost.objects.all().values_list("id", "host")
 
def index(request):
    form = DBHost()
    return render(request,"index.html",{"form":form})

给Form表单返回数据: Form表单可以返回默认数据,我们可以通过编号查询到指定数据的默认参数,并返回到编辑框中.

 
# name:views.py
from django.shortcuts import render
from django.forms import Form,fields,widgets
from MyWeb import models
 
class MyForm(Form):
    host = fields.CharField(required=True,widget=widgets.TextInput())
    title = fields.CharField(required=True, widget=widgets.TextInput())
 
def index(request):
    nid = request.GET.get("id")   # 通过ID获取到记录
    qset = models.DBHost.objects.filter(id=nid).values("host","title")
    dic = qset[0]  # 转为字典
 
    form = MyForm(dic) # 传递到前端编辑框中
    return render(request,"index.html",{"form":form})

	python manage.py shell #进入django shell
	python manage.py dbshell #进入django dbshell
	python manage.py check #检查django项目完整性
	python manage.py flush #清空数据库
	python manage.py compilemessages #编译语言文件
	python manage.py makemessages #创建语言文件
	python manage.py showmigrations #查看生成的数据库同步脚本
	python manage.py sqlflush #查看生成清空数据库的脚本
	python manage.py sqlmigrate #查看数据库同步的sql语句
	python manage.py dumpdata #导出数据
	python manage.py loaddata #导入数据
	python manage.py diffsettings #查看你的配置和django默认配置的不同之处

	MIDDLEWARE = [
	'django.middleware.csrf.CsrfViewMiddleware', # 为了能够开心玩耍,把这个干掉
	]

	INSTALLED_APPS = [
	'django.contrib.admin',
	'django.contrib.auth',
	'django.contrib.contenttypes',
	'django.contrib.sessions',
	'django.contrib.messages',
	'django.contrib.staticfiles',
	'MyWeb.apps.MywebConfig' # 导入
	]

	from MyWeb import views # 导入

	urlpatterns = [
	path('admin/', admin.site.urls),
	path('hello/',views.hello)
	]

	from django.shortcuts import HttpResponse

	# Create your views here.
	# 这个request必须加,不然会报错
	def hello(request):
	return HttpResponse("<h1>hello lyshark</h1>")

	# Static files (CSS, JavaScript, Images)
	# https://docs.djangoproject.com/en/3.0/howto/static-files/

	# 这个路径是对应 src="/static/ 的别名
	# 如果这个路径改为 STATIC_URL = '/abc/' 那么<script src="/abc/xxx.js"></script>
	STATIC_URL = '/static/'
	STATICFILES_DIRS = (
	os.path.join(BASE_DIR,'static'),
	)

	D:\> pip install django # 安装
	D:\> django-admin startproject MyProject # 创建项目
	D:\MyProject> django-admin startapp MyWeb # 创建APP
	D:\MyProject> python manage.py runserver 0.0.0.0:80 # 启动Django

	D:\MyProject> python manage.py shell # 进入Django交互shell
	D:\MyProject> python manage.py dbshell # 进入DBShell
	D:\MyProject> python manage.py check # 检查Django完整性

	MIDDLEWARE = [
	'django.middleware.security.SecurityMiddleware',
	'django.contrib.sessions.middleware.SessionMiddleware',
	'django.middleware.common.CommonMiddleware',
	#'django.middleware.csrf.CsrfViewMiddleware', # 注释掉此行
	'django.contrib.auth.middleware.AuthenticationMiddleware',
	]
	INSTALLED_APPS = [
	'django.contrib.admin',
	'django.contrib.auth',
	'django.contrib.contenttypes',
	'django.contrib.sessions',
	'django.contrib.messages',
	'django.contrib.staticfiles',
	'MyWeb.apps.MywebConfig' # 添加此行,导入我们的APP的名字
	]

	from MyWeb import views

	urlpatterns = [
	path('admin/', admin.site.urls),
	path("hello/",views.hello,name="hello")
	]

	# Static files (CSS, JavaScript, Images)
	# https://docs.djangoproject.com/en/3.0/howto/static-files/
	# 此时我们的默认路径是/static/,那么前端就可以直接调用<script src="/static/lyshark.js">
	STATIC_URL = '/static/'
	STATICFILES_DIRS=(
	os.path.join(BASE_DIR,'static')
	)

	urlpatterns = [
	path('admin/', admin.site.urls),
	path('',views.index,name="index"), # 一条访问主站的路由
	path('login/id=<int:id>&name=<str:name>',views.login,name="login"), # 名称后面传递参数
	path('add/<int:x>/<int:y>/',views.add,name="add") # 路径中传递参数
	]

	from django.shortcuts import render,HttpResponse
	def index(request):
	return render(request,"index.html")

	def login(request, id, name):
	return HttpResponse("用户ID{} , 用户名{} ".format(id,name))

	def add(request,x,y):
	temp = int(x)+int(y)
	return HttpResponse("相加结果:{}".format(temp))

	用户名: {{ user }} 密码:{{ pasd }} 标题:{{ title }}:

	def index(request):
	username = "lyshark"
	password = "123123"
	title = "hello lyshark"
	return render(request,"index.html",{"user":username,"pasd":password,"title":title})

	用户名: {{ user }} 密码:{{ pasd }} 标题:{{ title }}:

	def index(request):
	username = "admin"
	password = "123123"
	title = "hello lyshark"

	dict = {
	"user": username,
	"pasd": password,
	"title": title
	}
	return render(request,"index.html",dict)

	站点名称:{{ info.site }} 站点描述:{{ info.content }}:

	def index(request):
	info = {"site":"blib.cn","content":"hello lyshark"}
	return render(request,"index.html",{"info":info})

	{% for item in total %}
	打印数据: {{ item }}:<br>
	{% endfor %}

	def index(request):
	lists = ["HTML","CSS","JAVASCRIPT","Python","JQuery"]
	return render(request,"index.html",{"total":lists})

	{% for item in total reversed%}
	打印数据: {{ item }}:<br>
	{% endfor %}

	def index(request):
	lists = ["1","2","3","4","5"]
	return render(request,"index.html",{"total":lists})

	{% for key,value in info.items %}
	{{ key }} : {{ value }}
	{% endfor %}

	def index(request):
	info = {"site":"blib.cn","content":"hello lyshark"}
	info1 = {"site": "blib.cn", "content": "hello admin"}

	return render(request,"index.html",{"info":info,"info1":info1})

	<a href="{{ request.path }}?uid=1">当前网址加参数</a>

	<!--获取当前路径拼接成 /add/4/5-->
	{{ request.path }}{% url 'add' 4 5 %}

	def add(request,x,y):
	temp = int(x)+int(y)
	return HttpResponse("相加结果:{}".format(temp))

	def index(request):
	return render(request,"index.html")

	{% if request.user.is_authenticated %}
	{{ request.user.username }}，您好！
	{% else %}
	请登陆，这里放登陆链接
	{% endif %}

	{% if username == "lyshark" and password == "123123" %}
	恭喜你:
	{% elif username == "admin" or password == "123123" %}
	欢迎管理员:
	{% else %}
	这个都不是:
	{% endif %}

	def index(request):
	username = "admin"
	password = "123123"
	return render(request,"index.html",{"username":username,"password":password})

	{% if 1 in list %}
	在里面:
	{% elif 10 not in list %}
	不在里面:
	{% endif %}

	def index(request):
	list = [1,2,3,4,5]
	return render(request,"index.html",{"list":list})

	{% for item in info %}
	{% if forloop.first %}
	开始了:
	{% endif %}
	{{ forloop.counter }} : {{ item }}<br>
	{% if forloop.last %}
	最后了:
	{% endif %}
	{% endfor %}

	def index(request):
	list = map(str,range(100))
	return render(request,"index.html",{"info":list})

	forloop.counter 索引从 1 开始算
	forloop.counter0 索引从 0 开始算
	forloop.revcounter 索引从最大长度到 1
	forloop.revcounter0 索引从最大长度到 0
	forloop.first 当遍历的元素为第一项时为真
	forloop.last 当遍历的元素为最后一项时为真
	forloop.parentloop
	用在嵌套的 for 循环中，获取上一层 for 循环的 forloop

	列表长度: {{ total \| length }}:<br>
	输出大小: {{ size \| filesizeformat }}:<br>
	输出时间: {{ date \| date:"Y-m-d" }}:<br>
	首字母大写: {{ title \| capfirst }}:<br>
	从字符串中移除hello字符: {{title \| cut:"hello" }}:<br>
	显示字符串第一个元素: {{ total \| first }}:<br>
	显示字符串最后一个元素: {{ total \| last }}:<br>
	大小写转换(upper/lower): {{ title \| upper }}:<br>
	对数据切片: {{ title \| slice:"2:-1" }}:<br>
	截断字符：{{ title \| truncatechars:5 }}:<br>
	截断单词：{{ title \| truncatewords:1 }}:

	def index(request):
	filesize = 10240
	title = "hello lyshark"
	date = datetime.datetime.now()
	lists = ["1","2","3","4","5"]
	return render(request,"index.html",{"total":lists,"size":filesize,"date":date,"title":title})

	MyWeb/
	__init__.py
	models.py
	templatetags/
	__init__.py
	mysimple.py
	views.py

	from django import template
	from django.utils.safestring import mark_safe

	register = template.Library() # 此处必须这样写

	# simple_tag（自定义标签）：不会限制传参,但不支持if
	@register.simple_tag
	def simple_time(var1,var2,var3):
	temp = int(var1)+int(var2)+int(var3)
	return temp

	# filter（自定义过滤器）：限制传参2个,但支持if
	@register.filter
	def My_filter(value, arg):
	# 传递一个参数的过滤器
	return str.upper(value) + arg

	# name: views.py
	def index(request):
	title = "hello"
	return render(request,"index.html",{"title":title})

	# name: index.html
	<!--引入自定义的过滤器-->
	{% load mysimple %}

	自定义标签返回数值: {% simple_time 10 20 30 %}: <!-- 传递多个参数 -->
	传递一个参数的过滤器: {{ title \| My_filter:'lyshark' }}: <!-- 传递一个参数 -->

	母板： {% block title %}{% endblock %}
	子板继承： {% extends "base.html" %}
	子板中使用其他模板: {% include "xx.html" %}
	设置标题: {% block title %}{% endblock %}
	使用CSS资源: {% block css %} {% endblock %}
	使用JS资源: {% block js %} {% endblock %}

	<html>
	<head>
	<meta charset="UTF-8">
	{% block css %}{% endblock %}
	</head>
	<body>
	<div class="pg-body">
	<div class="body-menu">
	<ul>
	<li><a href="/user">用户管理</a></li>
	<li><a href="/hosts">资产管理</a></li>
	</ul>
	</div>
	<div class="body-content">
	{% block body %}{% endblock %} <!--占位符,用于填充子版块-->
	</div>
	</div>
	{% block js %}{% endblock %}
	</body>
	</html>

	{% extends 'base.html' %}
	{% block js %} {% endblock %}
	{% block css %} {% endblock %}

	{% block body %}
	<table>
	{% for item in host %}
	<tr>
	<td>{{ item.hostname }}</td>
	<td>{{ item.port }}</td>
	</tr>
	{% endfor %}
	</table>
	{% endblock %}

	from django.contrib import admin
	from django.urls import path
	from MyWeb import views

	urlpatterns = [
	path('admin/', admin.site.urls),
	path('',views.index,name="index"),
	path('hosts/',views.hosts,name="hosts"),
	path('user/',views.userinfo,name="user")
	]

	from django.shortcuts import render
	from django.shortcuts import HttpResponse

	def index(request):
	return render(request,"base.html")

	def hosts(request):
	hosts_list = []
	for i in range(10):
	temp = {'hostname':'192.168.1.'+str(i),'port':80}
	hosts_list.append(temp)
	return render(request,'hosts.html',{'host':hosts_list})

	def userinfo(request):
	user_list = []
	for i in range(10):
	temp = {'username': 'user' + str(i),'salary':80}
	user_list.append(temp)
	return render(request,'user.html',{'user_list':user_list})