django 自定义分页,网址存储缓存,CBV

1.

通过切片控制分页

自定义分页:

 from django.shortcuts import render

 # Create your views here.

 from app01.models import Book
 from django.core.paginator import Paginator,EmptyPage
 def index(request):

     '''

     批量插入数据：
         # for i in range(100):
         #     Book.objects.create(title="book_%s"%i,price=i*i)

         book_list=[]

         for i in range(100):
             book=Book(title="book_%s"%i,price=i*i)
             book_list.append(book)

         Book.objects.bulk_create(book_list)

     分页器的使用：
                 paginator=Paginator(book_list,8)

                 print(paginator.count) # 100
                 print(paginator.num_pages) # 分页数：13
                 print(paginator.page_range) # range(1, 14)

                 page=paginator.page(5)
                 for i in page:
                     print(i)

                 print(page.has_next())
                 print(page.has_previous())
                 print(page.next_page_number())
                 print(page.previous_page_number())

                     book_list = Book.objects.all()
                     paginator = Paginator(book_list, 2)
                     try:

                         current_page_num=request.GET.get("page",1)
                         current_page=paginator.page(current_page_num)
                     except EmptyPage as e:
                         current_page_num=1
                         current_page = paginator.page(1)

     '''
     # 自定义分页

     print(request.GET)

     from app01.page import Pagination
     current_page_num = request.GET.get("page")
     book_list = Book.objects.all()
     pagination=Pagination(current_page_num,book_list.count(),request)
     '''

     count=100
     per_page=9

     current_page_num=1       start 0     end 8
     current_page_num=2       start 8     end 16
     current_page_num=3       start 16    end 24
     current_page_num=n       start (n-1)*per_page    end n*per_page

     '''
     book_list=book_list[pagination.start:pagination.end]

     return render(request,"index.html",locals())

View

 """
 分页组件使用示例：

     obj = Pagination(request.GET.get('page',1),len(USER_LIST),request.path_info)
     page_user_list = USER_LIST[obj.start:obj.end]
     page_html = obj.page_html()

     return render(request,'index.html',{'users':page_user_list,'page_html':page_html})

 """

 class Pagination(object):

     def __init__(self,current_page_num,all_count,request,per_page_num=2,pager_count=11):
         """
         封装分页相关数据
         :param current_page_num: 当前访问页的数字
         :param all_count:    分页数据中的数据总条数
         :param per_page_num: 每页显示的数据条数
         :param pager_count:  最多显示的页码个数
         """
         try:
             current_page_num = int(current_page_num)
         except Exception as e:
             current_page_num = 1

         if current_page_num <1:
             current_page_num = 1

         self.current_page_num = current_page_num

         self.all_count = all_count
         self.per_page_num = per_page_num

         # 实际总页码
         all_pager, tmp = divmod(all_count, per_page_num)
         if tmp:
             all_pager += 1
         self.all_pager = all_pager

         self.pager_count = pager_count
         self.pager_count_half = int((pager_count - 1) / 2)  #

         # 保存搜索条件

         import copy
         self.params=copy.deepcopy(request.GET) # {"a":"1","b":"2"}

     @property
     def start(self):
         return (self.current_page_num - 1) * self.per_page_num

     @property
     def end(self):
         return self.current_page_num * self.per_page_num

     def page_html(self):
         # 如果总页码 < 11个：
         if self.all_pager <= self.pager_count:
             pager_start = 1
             pager_end = self.all_pager + 1
         # 总页码  > 11
         else:
             # 当前页如果<=页面上最多显示11/2个页码
             if self.current_page_num <= self.pager_count_half:
                 pager_start = 1
                 pager_end = self.pager_count + 1#尾页是固定的
             # 当前页大于5
             else:
                 # 页码翻到最后
                 if (self.current_page_num + self.pager_count_half) > self.all_pager:

                     pager_start = self.all_pager - self.pager_count + 1
                     pager_end = self.all_pager + 1#尾页是固定的

                 else:
                     pager_start = self.current_page_num - self.pager_count_half#+5 -5
                     pager_end = self.current_page_num + self.pager_count_half + 1

         page_html_list = []

         first_page = '<li><a href="?page=%s">首页</a></li>' % (1,)
         page_html_list.append(first_page)

         if self.current_page_num <= 1:
             prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
         else:
             prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page_num - 1,)

         page_html_list.append(prev_page)

         #self.params=copy.deepcopy(request.GET) # {"a":"1","b":"2"}

         for i in range(pager_start, pager_end):
             #照道理来说,深拷贝是不可以添加或修改的,但是这里是可以的
             #在返回的请求中通过添加page间而进行定位

             self.params["page"]=i

             if i == self.current_page_num:
                 temp = '<li class="active"><a href="?%s">%s</a></li>' %(self.params.urlencode(),i)
             else:
                 temp = '<li><a href="?%s">%s</a></li>' % (self.params.urlencode(),i,)
             page_html_list.append(temp)

         if self.current_page_num >= self.all_pager:
             next_page = '<li class="disabled"><a href="#">下一页</a></li>'
         else:
             next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page_num + 1,)
         page_html_list.append(next_page)
         last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
         page_html_list.append(last_page)

         return ''.join(page_html_list)

page.py

 <!DOCTYPE html>
 <html lang="zh-CN">
 <head>
     <meta charset="UTF-8">
     <title>Title</title>
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <!-- 最新版本的 Bootstrap 核心 CSS 文件 -->
 <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
 </head>
 <body>

 <ul>
     {% for book in book_list %}
     <li>{{ book.title }} ---- {{ book.price }}</li>
     {% endfor %}
 </ul>

 <nav aria-label="Page navigation">
   <ul class="pagination">
    {{ pagination.page_html|safe }}......
   </ul>
 </nav>

 </body>
 </html>

login.html

2.

 FBV-----function based view
 CBV-----class  based view

     path('index/', views.index),
     path('login/', views.LoginView.as_view()),
     path('login/', View.as_view.view)
     # 用户访问get请求/login/-----------view(request)

     def view(request):
         self = cls(**initkwargs)
         return self.dispatch(request, *args, **kwargs)

         def dispatch(request, *args, **kwargs):
                 if request.method.lower() in self.http_method_names:
                     handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
                 else:
                     handler = self.http_method_not_allowed
                 return handler(request, *args, **kwargs)
     

CBV源码

 from django.contrib import admin
 from django.urls import path

 from app01 import views

 urlpatterns = [
     path('admin/', admin.site.urls),
     path('login/', views.LoginView.as_view()),
 ]

urls

过程, as_view-- def view -- def dispatch --进行校验,返回