分页和中间件
一、分页
Django的分页器（paginator）
view.py
from django.shortcuts import render,HttpResponse
# Create your views here.
from app01.models import *
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
def index(request):
'''
批量导入数据:
Booklist=[]
for i in range(100):
Booklist.append(Book(title="book"+str(i),price=30+i*i))
Book.objects.bulk_create(Booklist)
'''
'''
分页器的使用:
book_list=Book.objects.all()
paginator = Paginator(book_list, 10)
print("count:",paginator.count) #数据总数
print("num_pages",paginator.num_pages) #总页数
print("page_range",paginator.page_range) #页码的列表
page1=paginator.page(1) #第1页的page对象
for i in page1: #遍历第1页的所有数据对象
print(i)
print(page1.object_list) #第1页的所有数据
page2=paginator.page(2)
print(page2.has_next()) #是否有下一页
print(page2.next_page_number()) #下一页的页码
print(page2.has_previous()) #是否有上一页
print(page2.previous_page_number()) #上一页的页码
# 抛错
#page=paginator.page(12) # error:EmptyPage
#page=paginator.page("z") # error:PageNotAnInteger
'''
book_list=Book.objects.all()
paginator = Paginator(book_list, 10)
page = request.GET.get('page',1)
currentPage=int(page)
try:
print(page)
book_list = paginator.page(page)
except PageNotAnInteger:
book_list = paginator.page(1)
except EmptyPage:
book_list = paginator.page(paginator.num_pages)
return render(request,"index.html",{"book_list":book_list,"paginator":paginator,"currentPage":currentPage})
view.py
def chakanbook(request):
'''
批量导入
Booklist = []
for i in range(100):
Booklist.append(models.Book(title="book" + str(i), price=20 + i * i))
models.Book.objects.bulk_create(Booklist)
:param request:
:return:
'''
book_list = models.Book.objects.all()# book_list打印的是一个对象 先查看所有的书
paginator=Paginator(book_list,5) #这里的book_list必须是一个集合对象，把所有的书分页，一页有五个
print(paginator.page_range) #range(1, 4)
num = request.GET.get("page",2)#得到页数范围,默认有1页
print(num,type(num))
book_list = paginator.page(num) #显示第一页的内容
return render(request,"chakan.html",{"book_list":book_list,"page_range":page_range,"num":int(num),"paginator":paginator})
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"
integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
</head>
<body>
<div class="container">
<h4>分页器</h4>
<ul>
{% for book in book_list %}
<li>{{ book.title }} -----{{ book.price }}</li>
{% endfor %}
</ul>
<ul class="pagination" id="pager">
{% if book_list.has_previous %}
<li class="previous"><a href="/index/?page={{ book_list.previous_page_number }}">上一页</a></li>
{% else %}
<li class="previous disabled"><a href="#">上一页</a></li>
{% endif %}
{% for num in paginator.page_range %}
{% if num == currentPage %}
<li class="item active"><a href="/index/?page={{ num }}">{{ num }}</a></li>
{% else %}
<li class="item"><a href="/index/?page={{ num }}">{{ num }}</a></li>
{% endif %}
{% endfor %}
{% if book_list.has_next %}
<li class="next"><a href="/index/?page={{ book_list.next_page_number }}">下一页</a></li>
{% else %}
<li class="next disabled"><a href="#">下一页</a></li>
{% endif %}
</ul>
</div>
</body>
</html>
扩展
def index(request):
book_list=Book.objects.all()
paginator = Paginator(book_list, 15)
page = request.GET.get('page',1)
currentPage=int(page)
# 如果页数十分多时，换另外一种显示方式
if paginator.num_pages>30:
if currentPage-5<1:
pageRange=range(1,11)
elif currentPage+5>paginator.num_pages:
pageRange=range(currentPage-5,paginator.num_pages+1)
else:
pageRange=range(currentPage-5,currentPage+5)
else:
pageRange=paginator.page_range
try:
print(page)
book_list = paginator.page(page)
except PageNotAnInteger:
book_list = paginator.page(1)
except EmptyPage:
book_list = paginator.page(paginator.num_pages)
return render(request,"index.html",locals())
二、中间件
http://www.cnblogs.com/yuanchenqi/articles/7652353.html#_label0