【Django】学习笔记

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MVC与MTV

MVC设计模式

MTV设计模式

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Django下载

pip install django==2.2.5

Django工程创建与运行

创建工程

django-admin startproject book_manager

运行工程

python manage.py runserver

子应用创建与注册安装

创建子应用

python manage.py startapp book

注册安装子应用

• 配置settings.py中的INSTALLED_APPS

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'book.apps.BookConfig',
]

数据模型

ORM框架

• 配置models.py

from django.db import models


# Create your models here.

# 书籍信息表
class BookInfo(models.Model):
    name = models.CharField(max_length=10, verbose_name='书籍名称')
    pub_date = models.DateField(null=True, verbose_name='出版日期')
    read_count = models.IntegerField(default=0, verbose_name='阅读量')
    comment_count = models.IntegerField(default=0, verbose_name='评论量')
    is_delete = models.BooleanField(default=False, verbose_name='是否删除')

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'book_info'
        verbose_name = '书籍信息管理'
        verbose_name_plural = verbose_name


# 人物信息表
class PersonInfo(models.Model):
    GENDER_CHOICES = (
        (0, 'male'),
        (1, 'female')
    )

    name = models.CharField(max_length=10, verbose_name='人物名称')
    gender = models.SmallIntegerField(choices=GENDER_CHOICES, default=0, verbose_name='人物性别')
    description = models.CharField(max_length=100, null=True, verbose_name='人物描述')
    book = models.ForeignKey(BookInfo, on_delete=models.CASCADE, verbose_name='人物所属书籍')
    is_delete = models.BooleanField(default=False, verbose_name='是否删除')

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'person_info'
        verbose_name = '人物信息管理'
        verbose_name_plural = verbose_name

模型迁移

• Tools->Run manage.py Task

makemigrations

migrate

Admin站点

修改语言和时区

• 配置settings.py

LANGUAGE_CODE = 'zh-hans'

TIME_ZONE = 'Asia/Shanghai'

设置管理员账号密码

• Tools->Run manage.py Task

createsuperuser

模型注册

• 配置admin.py

from django.contrib import admin

# Register your models here.

from .models import BookInfo, PersonInfo

admin.site.register(BookInfo)
admin.site.register(PersonInfo)

显示对象名称

from django.db import models


# Create your models here.

# 书籍信息表
class BookInfo(models.Model):
    name = models.CharField(max_length=10)

    def __str__(self):
        return self.name


# 人物信息表
class PersonInfo(models.Model):
    name = models.CharField(max_length=10)
    gender = models.BooleanField()
    book = models.ForeignKey(BookInfo, on_delete=models.CASCADE)

    def __str__(self):
        return self.name

模型显示中文

from django.db import models


# Create your models here.

# 书籍信息表
class BookInfo(models.Model):
    name = models.CharField(max_length=10)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = '书籍信息管理'
        verbose_name_plural = verbose_name


# 人物信息表
class PersonInfo(models.Model):
    name = models.CharField(max_length=10)
    gender = models.BooleanField()
    book = models.ForeignKey(BookInfo, on_delete=models.CASCADE)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name = '人物信息管理'
        verbose_name_plural = verbose_name

App显示中文

• 配置apps.py

from django.apps import AppConfig


class BookConfig(AppConfig):
    name = 'book'
    verbose_name = '书籍管理'

视图函数与路由系统

定义视图函数

• 配置views.py

from django.shortcuts import render

# Create your views here.

from django.http import HttpResponse


def index(request):
    return HttpResponse('OK!')

配置路由系统

• 创建子路由：在book文件夹下建立urls.py文件

from django.urls import path
from . import views

urlpatterns = [
    path('index/', views.index),
]

• 配置总路由

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('book.urls'))
]

模板渲染

配置模板路径

• 在项目根路径下建立templates文件夹
• 配置settings.py

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

• 在templates文件夹下建立book文件夹

建立视图

def index_2(request):
    context = {
        'name': '从心',
        'age': '22'
    }

    return render(request, template_name='book/index_2.html', context=c ontext)

建立模板

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>index_2</title>
</head>

<body>
    <div>
        书籍列表
        <ul>
            <li>西游记</li>
            <li>三国演义</li>
        </ul>
    </div>


    <div>
        个人信息
        <div>{{ name }}</div>
        <div>{{ age }}</div>
    </div>

</body>

</html>

配置文件与静态文件

BASE_DIR

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

DEBUG

DEBUG = True

• 默认工作在DEBUG模式下
• 修改源代码程序会自动重启
• Django程序出现异常时会向前端显示详细的错误追踪信息

DEBUG = False

ALLOWED_HOSTS = ['*']

• ALLOWED_HOSTS为指定的IP访问白名单

静态文件

• 在项目根目录下建立static文件夹
• STATIC_URL是静态文件访问路由
• STATICFILES_DIRS是静态文件存放路径

STATIC_URL = '/static/'

STATICFILES_DIRS = [
    os.path.join(BASE_DIR, 'static')
]

• 通过http://127.0.0.1:8000/static/1.jpg访问静态文件

数据库配置

建立数据库book_manager

• 字符集：utf8mb4
• 排序规则：utf8mb4_bin

配置settings.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'HOST': 'localhost',
        'PORT': 3306,
        'USER': 'root',
        'PASSWORD': 'root',
        'NAME': 'book_manager',
    }
}

安装MySQL驱动

• 配置__init__.py

import pymysql

pymysql.install_as_MySQLdb()

• 测试运行，修改最后一个链接

if query is not None:
	query = query.encode(errors='replace')

数据插入

insert into book_info (name, pub_date, read_count, comment_count, is_delete) values
('射雕英雄传', '1980-5-1', 12, 34, 0),
('天龙八部', '1986-7-24', 36, 40, 0),
('笑傲江湖', '1995-12-24', 20, 80, 0),
('雪山飞狐', '1987-11-11', 58, 24, 0);

insert into person_info (name, gender, description, book_id, is_delete) values
('郭靖', 0, '降龙十八掌', 1, 0),
('黄蓉', 1, '打狗棍法', 1, 0),
('黄药师', 0, '弹指神功', 1, 0),
('欧阳锋', 0, '蛤蟆功', 1, 0),
('梅超风', 1, '九阴白骨爪', 1, 0),
('乔峰', 0, '降龙十八掌', 2, 0),
('段誉', 0, '六脉神剑', 2, 0),
('虚竹', 0, '天山六阳掌', 2, 0),
('王语嫣', 1, '神仙姐姐', 2, 0),
('令狐冲', 0, '独孤九剑', 3, 0),
('任盈盈', 1, '弹琴', 3, 0),
('岳不群', 0, '华山剑法', 3, 0),
('东方不败', 1, '葵花宝典', 3, 0),
('胡斐', 0, '胡家刀法', 4, 0),
('苗若兰', 1, '黄衣', 4, 0),
('程灵素', 1, '医术', 4, 0),
('袁紫衣', 1, '六合拳', 4, 0);

数据增加

save()方法

from book.models import BookInfo

book_info = BookInfo(
    name='完美世界',
    pub_date='2013-8-16'
)

book_info.save()

objects.create()方法

from book.models import BookInfo

BookInfo.objects.create(
    name='斗破苍穹',
    pub_date='2014-5-4'
)

数据修改

save()方法

from book.models import BookInfo

book_info = BookInfo.objects.get(id=5)
book_info.name = '斗罗大陆'

book_info.save()

objects.filter().update()方法

from book.models import BookInfo

BookInfo.objects.filter(id=6).update(name='炼气十万年')

数据删除

delete()方法

from book.models import BookInfo

book_info = BookInfo.objects.get(id=6)

book_info.delete()

objects.filter().delete()方法

from book.models import BookInfo

BookInfo.objects.filter(id=5).delete()

数据库查询

基础查询

objects.all()方法

from book.models import BookInfo

BookInfo.objects.all()

objects.count()方法

from book.models import BookInfo

BookInfo.objects.all()

objects.exclude()方法

from book.models import BookInfo

BookInfo.objects.exclude(id=1)

objects.filter()方法

from book.models import BookInfo

BookInfo.objects.filter(id=1)[0]

过滤查询

exact

from book.models import BookInfo

BookInfo.objects.get(id__exact=1)

contains

from book.models import BookInfo

BookInfo.objects.filter(name__contains='湖')

endswith

from book.models import BookInfo

BookInfo.objects.filter(name__endswith='部')

isnull

from book.models import BookInfo

BookInfo.objects.filter(name__isnull=True)

in

from book.models import BookInfo

BookInfo.objects.filter(id__in=[1, 3, 5])

gt

from book.models import BookInfo

BookInfo.objects.filter(id__gt=3)

year

from book.models import BookInfo

BookInfo.objects.filter(pub_date__year=1980)

gte

from book.models import BookInfo

BookInfo.objects.filter(pub_date__gte='1990-1-1')

F对象

from book.models import BookInfo

from django.db.models import F

BookInfo.objects.filter(read_count__gt=F('comment_count') * 2)

Q对象

逻辑与

objects.filter()方法

from book.models import BookInfo

BookInfo.objects.filter(read_count__gt=20, id__lt=3)
# BookInfo.objects.filter(read_count__gt=20).filter(id__lt=3)

Q对象

from book.models import BookInfo

from django.db.models import Q

BookInfo.objects.filter(Q(read_count__gt=20) & Q(id__lt=3))

逻辑或

from book.models import BookInfo

from django.db.models import Q

BookInfo.objects.filter(Q(read_count__gt=20) | Q(id__lt=3))

逻辑非

from book.models import BookInfo

from django.db.models import Q

BookInfo.objects.filter(~Q(id=1))

聚合函数

from book.models import BookInfo

from django.db.models import Sum, Max, Min, Avg, Count

BookInfo.objects.aggregate(Sum('read_count'))

排序函数

正序

from book.models import BookInfo

BookInfo.objects.all().order_by('read_count')

倒序

from book.models import BookInfo

BookInfo.objects.all().order_by('-read_count')

关联查询

访问

一对多的访问

from book.models import BookInfo

book = BookInfo.objects.get(id=1)

book.personinfo_set.all()

多对一的访问

from book.models import PersonInfo

person = PersonInfo.objects.get(id=1)

person.book

# person.book_id
person.book.id

过滤查询

多对一的查询

from book.models import BookInfo

book = BookInfo.objects.filter(personinfo__name='郭靖')

book

book = BookInfo.objects.filter(personinfo__description__contains='八')

book

一对多的查询

from book.models import PersonInfo

people = PersonInfo.objects.filter(book__name='天龙八部')

people

people = PersonInfo.objects.filter(book__read_count__gt=20)

people

切片

from book.models import BookInfo

BookInfo.objects.all()[0:2]

分页

from book.models import BookInfo

from django.core.paginator import Paginator

books = BookInfo.objects.all()

paginator = Paginator(books, 2)

page_1_books = list(paginator.page(1))

page_1_books

paginator.num_pages

惰性执行

• 如果用变量接收查询语句的返回结果，那么查询语句不会立即执行，而是等到调用该变量时执行

from book.models import BookInfo

books = BookInfo.objects.all()

books

缓存

• 变量的值存放在系统内存中，如果通过变量进行查询，那么不会对数据库进行查询，而是从内存中查询

from book.models import BookInfo

books = BookInfo.objects.all()

[book.id for book in books]

[book.id for book in books]

HttpRequest

路由参数

配置views.py

def url_data(request, cat_id, sku_id):
    print(cat_id, sku_id)

    return HttpResponse('OK!')

配置urls.py

path('<cat_id>/<sku_id>/', views.url_data)

查询字符串

配置views.py

def query_str_data(request):
    print(request.GET)

    a = request.GET.get('a')
    b = request.GET.get('b')
    print(a, b)

    a_list = request.GET.getlist('a')
    print(a_list)

    return HttpResponse('OK!')

url

http://localhost:8000/query_str_data/?a=1&b=2&a=3

表单数据

配置views.py

def form_data(request):
    print(request.POST)

    username = request.POST.get('username')
    password = request.POST.get('password')

    print(username, password)

    return HttpResponse('OK!')

关闭CSRF

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    # 'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

JSON数据

配置views.py

def json_data(request):
    json_data = request.body
    dict_data = json.loads(json_data)

    print(dict_data['username'], dict_data['age'])

    return HttpResponse('OK!')

请求头数据

配置views.py

def headers_data(request):
    print(request.META)
    print(request.META['CONTENT_TYPE'])
    print(request.method)
    print(request.path)
    print(request.user)

    return HttpResponse('OK!')

转换器

配置converters.py

from django.urls.converters import register_converter


class TelConverter:
    regex = '1[3-9]\d{9}'

    def to_python(self, value):
        return int(value)

    def to_url(self, value):
        return str(value)


register_converter(TelConverter, 'tel')

配置views.py

import converters


def tel_data(request, tel_data):
    print(tel_data)

    return HttpResponse('OK!')

配置urls.py

path('<tel:tel_data>/',views.tel_data)

HttpResponse

配置views.py

def http_response(request):
    response = HttpResponse(content='OK!', content_type='text/plain', status=200)
    response['key'] = 'value'

    return response

JsonResponse

配置views.py

def json_response(request):
    books_info = [
        {
            'id': 1,
            'name': '射雕英雄传',
            'pub_date': '1980-5-1'
        },
        {
            'id': 2,
            'name': '天龙八部',
            'pub_date': '1986-7-24'
        }
    ]

    return JsonResponse(data=books_info, safe=False)

Redirect

配置views.py

from django.shortcuts import redirect


def redirect_url(request):
    return redirect('https://www.baidu.com')

Cookie

设置Cookie

配置views.py

def set_cookie(request):
    username = request.GET.get('username')
    password = request.GET.get('password')

    print(username, password)

    response = HttpResponse('OK!')
    response.set_cookie('username', username)
    response.set_cookie('password', password)

    return response

获取Cookie

配置views.py

def get_cookie(request):
    print(request.COOKIES)

    username = request.COOKIES.get('username')
    password = request.COOKIES.get('password')

    return HttpResponse(f'username: {username}, password: {password}')

Session

设置Session

配置views.py

def set_session(request):
    username = request.GET.get('username')
    user_id = 1

    request.session['username'] = username
    request.session['user_id'] = user_id

    del request.session['user_id']
    # request.session.clear()
    # request.session.flush()

    request.session.set_expiry(60)

    return HttpResponse('OK!')

获取Session

配置views.py

def get_session(request):
    username = request.session.get('username')
    user_id = request.session.get('user_id')

    return HttpResponse(f'username: {username}, user_id: {user_id}')

保存Session到Redis

配置settings.py

CACHES = {
    'default': {
        'BACKEND': 'django_redis.cache.RedisCache',
        'LOCATION': 'redis://127.0.0.1:6379/1',
        'OPTIONS': {
            'CLIENT_CLASS': 'django_redis.client.DefaultClient',
        }
    }
}

SESSION_ENGINE = 'django.contrib.sessions.backends.cache'
SESSION_CACHE_ALIAS = 'default'

类视图

类视图定义

配置views.py

from django.views import View


class LoginView(View):
    def get(self, request):
        return HttpResponse(f'当前请求为: {request.method}')

    def post(self, request):
        return HttpResponse(f'当前请求为: {request.method}')

配置urls.py

path('login/', views.LoginView.as_view())

多继承

配置views.py

from django.contrib.auth.mixins import LoginRequiredMixin


class OrderLoginView(LoginRequiredMixin, View):
    def get(self, request):
        return HttpResponse('个人中心页面')

    def post(self, request):
        return HttpResponse('个人中心页面')

中间件

中间件定义

配置middleware.py

from django.utils.deprecation import MiddlewareMixin


class TestMiddleware(MiddlewareMixin):
    def process_request(self, request):
        print('每次请求前, 进行调用')

        username = request.COOKIES.get('username')
        if username is None:
            print('用户信息不存在')
        else:
            print('用户信息存在')

    def process_response(self, request, response):
        print('每次响应前, 进行调用')

        return response

配置settings.py

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    # 'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    'book.middlewares.TestMiddleware'
]

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