分页和中间件

Posted 2022-12-20 maaosheng

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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

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