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())

"""
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)  # 5


        # 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)

<!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>

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)
    

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()),
]

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