分页和中间件

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):
</span><span style="color: #800000;">'''</span><span style="color: #800000;">
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)
</span><span style="color: #800000;">'''</span>

<span style="color: #800000;">'''</span><span style="color: #800000;">

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

</span><span style="color: #800000;">'''</span><span style="color: #000000;">


book_list</span>=<span style="color: #000000;">Book.objects.all()

paginator </span>= Paginator(book_list, 10<span style="color: #000000;">)
page </span>= request.GET.get(<span style="color: #800000;">'</span><span style="color: #800000;">page</span><span style="color: #800000;">'</span>,1<span style="color: #000000;">)
currentPage</span>=<span style="color: #000000;">int(page)


</span><span style="color: #0000ff;">try</span><span style="color: #000000;">:
    </span><span style="color: #0000ff;">print</span><span style="color: #000000;">(page)
    book_list </span>=<span style="color: #000000;"> paginator.page(page)
</span><span style="color: #0000ff;">except</span><span style="color: #000000;"> PageNotAnInteger:
    book_list </span>= paginator.page(1<span style="color: #000000;">)
</span><span style="color: #0000ff;">except</span><span style="color: #000000;"> EmptyPage:
    book_list </span>=<span style="color: #000000;"> paginator.page(paginator.num_pages)


</span><span style="color: #0000ff;">return</span> render(request,<span style="color: #800000;">"</span><span style="color: #800000;">index.html</span><span style="color: #800000;">"</span>,{<span style="color: #800000;">"</span><span style="color: #800000;">book_list</span><span style="color: #800000;">"</span>:book_list,<span style="color: #800000;">"</span><span style="color: #800000;">paginator</span><span style="color: #800000;">"</span>:paginator,<span style="color: #800000;">"</span><span style="color: #800000;">currentPage</span><span style="color: #800000;">"</span>:currentPage})</pre>

 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:
    </span><span style="color: #800000;">'''</span><span style="color: #000000;">
book_list </span>= models.Book.objects.all()<span style="color: #008000;">#</span><span style="color: #008000;"> book_list打印的是一个对象  先查看所有的书</span>
paginator=Paginator(book_list,5)  <span style="color: #008000;">#</span><span style="color: #008000;">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</span>
<span style="color: #0000ff;">print</span>(paginator.page_range)  <span style="color: #008000;">#</span><span style="color: #008000;">range(1, 4)</span><span style="color: #000000;">
num </span>= request.GET.get(<span style="color: #800000;">"</span><span style="color: #800000;">page</span><span style="color: #800000;">"</span>,2)<span style="color: #008000;">#</span><span style="color: #008000;">得到页数范围,默认有1页</span>
<span style="color: #0000ff;">print</span><span style="color: #000000;">(num,type(num))
book_list </span>= paginator.page(num) <span style="color: #008000;">#</span><span style="color: #008000;">显示第一页的内容</span>
<span style="color: #0000ff;">return</span> render(request,<span style="color: #800000;">"</span><span style="color: #800000;">chakan.html</span><span style="color: #800000;">"</span>,{<span style="color: #800000;">"</span><span style="color: #800000;">book_list</span><span style="color: #800000;">"</span>:book_list,<span style="color: #800000;">"</span><span style="color: #800000;">page_range</span><span style="color: #800000;">"</span>:page_range,<span style="color: #800000;">"</span><span style="color: #800000;">num</span><span style="color: #800000;">"</span>:int(num),"paginator":paginator})</pre>

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">
&lt;h4&gt;分页器&lt;/h4&gt;
&lt;ul&gt;

    {% for book in book_list %}
         &lt;li&gt;{{ book.title }} -----{{ book.price }}&lt;/li&gt;
    {% endfor %}

 &lt;/ul&gt;


&lt;ul class="pagination" id="pager"&gt;

             {% if book_list.has_previous %}
                &lt;li class="previous"&gt;&lt;a href="/index/?page={{ book_list.previous_page_number }}"&gt;上一页&lt;/a&gt;&lt;/li&gt;
             {% else %}
                &lt;li class="previous disabled"&gt;&lt;a href="#"&gt;上一页&lt;/a&gt;&lt;/li&gt;
             {% endif %}


             {% for num in paginator.page_range %}

                 {% if num == currentPage %}
                   &lt;li class="item active"&gt;&lt;a href="/index/?page={{ num }}"&gt;{{ num }}&lt;/a&gt;&lt;/li&gt;
                 {% else %}
                   &lt;li class="item"&gt;&lt;a href="/index/?page={{ num }}"&gt;{{ num }}&lt;/a&gt;&lt;/li&gt;

                 {% endif %}
             {% endfor %}



             {% if book_list.has_next %}
                &lt;li class="next"&gt;&lt;a href="/index/?page={{ book_list.next_page_number }}"&gt;下一页&lt;/a&gt;&lt;/li&gt;
             {% else %}
                &lt;li class="next disabled"&gt;&lt;a href="#"&gt;下一页&lt;/a&gt;&lt;/li&gt;
             {% endif %}

        &lt;/ul&gt;

</div>
</body>

</html>

扩展

def index(request):
book_list</span>=<span style="color: #000000;">Book.objects.all()

paginator </span>= Paginator(book_list, 15<span style="color: #000000;">)
page </span>= request.GET.get(<span style="color: #800000;">'</span><span style="color: #800000;">page</span><span style="color: #800000;">'</span>,1<span style="color: #000000;">)
currentPage</span>=<span style="color: #000000;">int(page)

</span><span style="color: #008000;">#</span><span style="color: #008000;">  如果页数十分多时，换另外一种显示方式</span>
<span style="color: #0000ff;">if</span> paginator.num_pages&gt;30<span style="color: #000000;">:

    </span><span style="color: #0000ff;">if</span> currentPage-5&lt;1<span style="color: #000000;">:
        pageRange</span>=range(1,11<span style="color: #000000;">)
    </span><span style="color: #0000ff;">elif</span> currentPage+5&gt;<span style="color: #000000;">paginator.num_pages:
        pageRange</span>=range(currentPage-5,paginator.num_pages+1<span style="color: #000000;">)

    </span><span style="color: #0000ff;">else</span><span style="color: #000000;">:
        pageRange</span>=range(currentPage-5,currentPage+5<span style="color: #000000;">)

</span><span style="color: #0000ff;">else</span><span style="color: #000000;">:
    pageRange</span>=<span style="color: #000000;">paginator.page_range


</span><span style="color: #0000ff;">try</span><span style="color: #000000;">:
    </span><span style="color: #0000ff;">print</span><span style="color: #000000;">(page)
    book_list </span>=<span style="color: #000000;"> paginator.page(page)
</span><span style="color: #0000ff;">except</span><span style="color: #000000;"> PageNotAnInteger:
    book_list </span>= paginator.page(1<span style="color: #000000;">)
</span><span style="color: #0000ff;">except</span><span style="color: #000000;"> EmptyPage:
    book_list </span>=<span style="color: #000000;"> paginator.page(paginator.num_pages)


</span><span style="color: #0000ff;">return</span> render(request,<span style="color: #800000;">"</span><span style="color: #800000;">index.html</span><span style="color: #800000;">"</span>,locals())</pre>

二、中间件

http://www.cnblogs.com/yuanchenqi/articles/7652353.html#_label0