Django入门
Django文档：
https://docs.djangoproject.com/en/1.10/ref/
一、简单创建app
1.1 命令行创建project和app。
django-admin startproject HelloWorld
cd HelloWorld
python manage.py startapp app01
1.2 pycharm创建app
2、将app01加入settings并配置url。
3、启动app
python manage.py runserver 8000
二、
生成环境：
settings.py
DEBUG = False
ALLOWED_HOSTS = ["*"]
2.1 配置加载html
或者通过render()返回html页面。
def login(request):
# content = open("templates/app01/login.html","r").read()
# return HttpResponse(content)
return render(request,"app01/login.html")
注意html里的加载的css,jq,js用http的方式或配置静态文件的方式引入。
2.2 django将表应用到数据库。
python manage.py makemigration #根据class创建创建数据库的配置文件
python manage.py migrate # 根据配置文件创建数据库表
2.3 django创建后台管理员账户
python manage.py createsuperuser
2.4 路由系统
动态路由，正则表达式： 
这个(\d+) 会传入news(request,nid)函数。
二级路由
首先创建app01, python manage.py startapp app02
from django.conf.urls import url,include
,在app01目录下的urls.py下配置urls
,在app02目录下的urls.py下配置urls
2.5 数据库操作
数据库连接：
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'day15',
'HOST':'127.0.0.1',
'PORT':'3306',
'USER':'root',
'PASSWORD':'root',
}
}
modles.py
class UserInfo(models.Model):
username = models.CharField(max_length=32)
password = models.CharField(max_length=32)
age = models.IntegerField()
# 默认会自动添加自增的id作为主键
一对多，多对多
class Author(models.Model):
first_name = models.CharField(max_length=32)
last_name = models.CharField(max_length=32)
email = models.EmailField()
class Publisher(models.Model):
name = models.CharField(max_length=64,unique=True)
address = models.CharField(max_length=128)
city = models.CharField(max_length=64)
state_province = models.CharField(max_length=30)
country = models.CharField(max_length=50)
website = models.URLField()
class Book(models.Model):
bookname = models.CharField(max_length=128)
authors = models.ManyToManyField(Author)
publisher = models.ForeignKey(Publisher)
publish_date = models.DateField()
然后，执行python manage.py makemigrations ; python manage.py migrate
E:\day15>python2 manage.py makemigrations
Migrations for 'app01':
app01\migrations\0002_auto_20160807_2043.py:
- Create model Author
- Create model Book
- Create model Publisher
- Add field publisher to book
E:\day15>python2 manage.py migrate
Operations to perform:
Apply all migrations: admin, app01, auth, contenttypes, sessions
Running migrations:
Rendering model states... DONE
Applying app01.0002_auto_20160807_2043... OK
会生成第三张表：
Django后台管理数据库。
首先在app01的admin.py下注册数据库表
import models # Register your models here. admin.site.register(models.UserInfo) admin.site.register(models.Author) admin.site.register(models.Book) admin.site.register(models.Publisher)
创建后台用户：
python manage.py createsuperuser
登录后台并操作表：
定制表在后台返回字符串：
class Author(models.Model):
first_name = models.CharField(max_length=32)
last_name = models.CharField(max_length=32)
email = models.EmailField()
def __unicode__(self):
return "author: %s %s"%(self.first_name,self.last_name)
后台样式：
由于book是需要关联其他标的，所以在新增book数据时，关联字段是不能任意填写的，只能选择：
修改字段：
first_name = models.CharField(max_length=32,null=True)
python manage.py makemigrations,python manage.py migrate
虽然数据库种这个字段可以为空，但是在Gjango后台还是不能以空插入数据：
要以空值插入数据，需要修改类中的表定义：
first_name = models.CharField(max_length=32,null=True,blank=True) """ blank¶ Field.blank¶ If True, the field is allowed to be blank. Default is False. Note that this is different than null. null is purely database-related, whereas blank is validation-related. If a field has blank=True, form validation will allow entry of an empty value. If a field has blank=False, the field will be required. """
参考文档：
https://docs.djangoproject.com/en/1.10/ref/models/fields/
增、删、改、查（针对userinfo表）
def db_h(request):
# 增
# models.UserInfo.objects.create(username="ds",password="123",age=18)
# 删
# models.UserInfo.objects.filter(username='ds').delete()
# 改
# models.UserInfo.objects.filter(age=18).update(age=20)
# models.UserInfo.objects.all().update(age=19)
# 查
userlist_obj = models.UserInfo.objects.all()
users = []
for user in userlist_obj:
users.append(user.username)
userstring = json.dumps(users)
# models.UserInfo.objects.filter(username='ds')
# models.UserInfo.objects.filter(age=18).first()
return HttpResponse(userstring)
模糊查找：参见官方文档。
https://docs.djangoproject.com/en/1.10/ref/models/querysets/
https://docs.djangoproject.com/en/1.10/topics/db/queries/
对于上面的多对多手动新增书籍：
E:\python27\day15>python2 manage.py shell >>> from datatime import datatime >>> p = models.Publisher.object.filter().first() >>> b = models.Book(bookname="OWASP",publish_date=datetime.now(),publisher=p) >>> b.save() >>> a = models.Author.objects.filter().first() >>> b.authors.add(a) >>> b.authors.remove(a)
数据库取数据，并将数据传入html
# app01.views
def db_h(request):
userlist_obj = models.UserInfo.objects.all()
return render(request,"app01/tables.html",{"li":userlist_obj})
# templates.app01.tables.html
<table>
<tr>
<th>姓名</th>
<th>密码</th>
<th>年龄</th>
</tr>
{% for item in li %}
<tr>
<td>{{ item.username}}</td>
<td>{{ item.password }}</td>
<td>{{ item.age }}</td>
</tr>
{% endfor %}
</table>
2,6 引入静态文件
注意要是列表或元组，
2.7 数据提交。
对于POST请求需在setttings里把跨站请求注释掉。# 'django.middleware.csrf.CsrfViewMiddleware',
我们可以通过POST和GET方式提交，提交到后台的数据通过request.GET或request.POST方式取得，request,method是提交的方法，值为"POST"或"GET"。
('val:', <QueryDict: {u'username': [u'gg'], u'age': [u'21'], u'password': [u'rr']}>) ， 这是在后台打印的POST方式的数据。我们可以通过request.POST["username"]获取username的值。
JSON数据转换：
# 将字典转为JSON格式（字符串）再发送给客户端
response_data_ok = {"status":"ok"}
return HttpResponse(json.dumps(response_data_ok))
# 客户端接收JSON格式的字符串后再反转为原来的格式
"success":function(msg1){
msg = JSON.parse(msg1)
}
未完待续
2.8 Template渲染
基本语法：
E:\day15>python2 manage.py shell
Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
>>> from django.template import Context,Template
>>> t = Template("My name is {{name}},I'am {{age}} years old")
>>> c = Context({"name":"DS","age":18})
>>> t.render(c)
u"My name is DS,I'am 18 years old"
>>> for i in [{"name":"DS","age":18},{"name":"lj","age":20}]:
... print(t.render(Context(i)))
...
My name is DS,I'am 18 years old
My name is lj,I'am 20 years old
>>>
# 深度变量查找1
>>> p = {"name":"ow","age":20}
>>> t1 = Template("My name is {{person.name}}")
>>> c = Context({'person':p})
>>> t1.render(c)
u'My name is ow'
# 深度变量查找2
>>> t = Template("My name is {{item.1}}")
>>> c = Context({"item":["ds","lj","cc"]})
>>> t.render(c)
u'My name is lj'
# 深度查找3（类）
>>> import datetime
>>> d = datetime.date(2016,8,7)
>>> d.year
2016
>>> t = Template("today is {{i.year}} {{i.month}} {{i.day}}")
>>> c = Context({"i":d})
>>> t.render(c)
u'today is 2016 8 7'
Template用于模板文件语法：
{% for item in li %}
<tr>
<td>{{ item.username}}</td>
<td>{{ item.password }}</td>
<td>{{ item.age }}</td>
</tr>
{% endfor %}
forloop.counter0 循环计数器
value}divisibleby:"2" 能被2整除
html继承和重写
模板app01/modle.html
<html>
<body>
<div>...</div>
{% block content %}
{% endblock %}
</body>
</html>
继承和重写app01/admin.html
{% extends "app01/modle.html" %}
{% block content %}
<div class="container">
<table class="table table-bordered table-hover ">
<tr>
<th>姓名</th>
<th>密码</th>
<th>年龄</th>
</tr>
{% for item in li %}
<tr>
<td>{{ item.username}}</td>
<td>{{ item.password }}</td>
<td>{{ item.age }}</td>
</tr>
{% endfor %}
</table>
</div>
{% endblock %}
导入
# weather.html
<div>
Weather
</div>
# login.html
{% include "app01/weather.html %}
