了解学习pyhton web的简单demo

1. 安装Django， 安装pyhton 自行百度

2. 执行命令创建project  django-admin.py startproject mysite

3. 执行命令创建app python manage.py startapp polls

目录结构：   polls/templates/polls 目录  和  polls/admin.py 都是自己手动创建的。

4. 编辑setting.py 添加app  polls  同时打开admin

INSTALLED_APPS = (

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.sites',

'django.contrib.messages',

'django.contrib.staticfiles',

'polls',

# Uncomment the next line to enable the admin:

'django.contrib.admin',

# Uncomment the next line to enable admin documentation:

# 'django.contrib.admindocs',

)

5. 编辑setting.py 添加数据库连接信息

DATABASES = {

'default': {

'ENGINE': 'django.db.backends.mysql', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.

'NAME': 'polls', # Or path to database file if using sqlite3.

'USER': 'root', # Not used with sqlite3.

'PASSWORD': '123', # Not used with sqlite3.

'HOST': '', # Set to empty string for localhost. Not used with sqlite3.

'PORT': '', # Set to empty string for default. Not used with sqlite3.

}

}

6. 创建Modle模型 ：

# coding=utf-8

from django.db import models

# Create your models here.

class Question(models.Model):

question_text = models.CharField(max_length=200)

pub_date = models.DateTimeField('date published')

def __unicode__(self):

return self.question_text

class Choice(models.Model):

question = models.ForeignKey(Question)

choice_text = models.CharField(max_length=200)

votes = models.IntegerField(default=0)

def __unicode__(self):

return self.choice_text

7.  执行数据库同步  (ORM)自动根据model定义创建表接口 (我这里使用的mysql)

首先创建数据库

create database polls;

然后执行命令：

python manage.py syncdb

8. 检查数据库中表的创建：

use polls

show tables

9. 创建admin.py

# coding=utf-8

from django.contrib import admin

from .models import Question, Choice

# Register your models here.

class ChoiceInline(admin.TabularInline):

model = Choice

extra = 3

class QuestionAdmin(admin.ModelAdmin):

fieldsets = [

(None, {'fields': ['question_text']}),

('Date information', {'fields': ['pub_date'], 'classes': ['collapse']}),

]

inlines = [ChoiceInline]

list_display = ('question_text', 'pub_date')

admin.site.register(Choice)

admin.site.register(Question, QuestionAdmin)

10. 启动应用

python manage.py runserver

11. 编写视图控制层

视图起着承前启后的作用，前是指前端页面，后是指后台数据库。将数据库表中的内容查询出来显示到页面上。

编写polls/views.py文件：

# coding=utf-8

from django.shortcuts import render, get_object_or_404

from django.http import HttpResponseRedirect, HttpResponse

from django.core.urlresolvers import reverse

from .models import Question, Choice

# Create your views here.

# 首页展示所有问题

def index(request):

# latest_question_list2 = Question.objects.order_by('-pub_data')[:2]

latest_question_list = Question.objects.all()

context = {'latest_question_list': latest_question_list}

return render(request, 'polls/index.html', context)

# 查看所有问题

def detail(request, question_id):

question = get_object_or_404(Question, pk=question_id)

return render(request, 'polls/detail.html', {'question': question})

# 查看投票结果

def results(request, question_id):

question = get_object_or_404(Question, pk=question_id)

return render(request, 'polls/results.html', {'question': question})

# 选择投票

def vote(request, question_id):

p = get_object_or_404(Question, pk=question_id)

try:

selected_choice = p.choice_set.get(pk=request.POST['choice'])

except (KeyError, Choice.DoesNotExist):

# Redisplay the question voting form.

return render(request, 'polls/detail.html', {

'question': p,

'error_message': "You didn't select a choice.",

})

else:

selected_choice.votes += 1

selected_choice.save()

# Always return an HttpResponseRedirect after successfully dealing

# with POST data. This prevents data from being posted twice if a

# user hits the Back button.

return HttpResponseRedirect(reverse('polls:results', args=(p.id,)))

12. 配置视图展示层与逻辑控制层url映射

url是一个请求配置文件，页面中的请求转交给由哪个函数处理，由该文件决定。

首先配置polls/urls.py(该文件需要创建)

from django.conf.urls import url

from . import views

urlpatterns = [

# ex : /polls/

url(r'^$', views.index, name='index'),

# ex : /polls/5/

url(r'^(?P[0-9]+)/$', views.detail, name='detail'),

# ex : /polls/5/results/

url(r'^(?P[0-9]+)/results/$', views.results, name='results'),

# ex : /polls/5/vote

url(r'^(?P[0-9]+)/vote/$', views.vote, name='vote'),

]

接着，编辑mysite/urls.py文件。

from django.conf.urls import include, url

from django.contrib import admin

urlpatterns = [

url(r'^polls/', include('polls.urls', namespace="polls")),

url(r'^admin/', include(admin.site.urls)),

]

13. 创建视图模板

模板就是前端页面，用来将数据显示到web页面上。

首先创建polls/templates/polls/目录，分别在该目录下创建index.html、detail.html和results.html文件。

index.html

{% if latest_question_list %}

{% for question in latest_question_list %}

{{ question.question_text }}

{% endfor %}

{% else %}

No polls are available.

{% endif %}

detail.html

{{ question.question_text }}

{% if error_message %}

{{ error_message }}

{% endif %}

{% csrf_token %}

{% for choice in question.choice_set.all %}

{{ choice.choice_text }}

{% endfor %}

results.html

{{ question.question_text }}

{% for choice in question.choice_set.all %}

{{ choice.choice_text }} -- {{ choice.votes }} vote{{ choice.votes|pluralize }}

{% endfor %}

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