一.Django的分页器
view
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) # 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())
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())
自定义分页(app01中的page.py)
""" 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 # 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 else: pager_start = self.current_page_num - self.pager_count_half 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): self.params["page"]=i if i == self.current_page_num: # 保存搜索条件 temp = '<li class="active"><a href="?%s">%s</a></li>' %(self.params.urlencode(),i) else: # 保存搜索条件 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)
index.html
<!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>
二.CBV
1.FBV
FBV(function base views) 就是在视图里使用函数处理请求。
2.CBV
CBV(class base views) 就是在视图里使用类处理请求。
优点:
- 提高了代码的复用性,可以使用面向对象的技术,比如Mixin(多继承)
- 可以用不同的函数针对不同的HTTP方法处理,而不是通过很多if判断,提高代码可读性
FBV
看代码:
urls.py
1
2
3
4
5
6
7
8
|
from django.conf.urls import url, include # from django.contrib import admin from mytest import views urlpatterns = [ # url(r‘^admin/‘, admin.site.urls), url(r‘^index / ‘, views.index), ] |
views.py
1
2
3
4
5
6
7
8
9
|
from django.shortcuts import render def index(req): if req.method = = ‘POST‘: print (‘method is :‘ + req.method) elif req.method = = ‘GET‘: print (‘method is :‘ + req.method) return render(req, ‘index.html‘) |
注意此处定义的是函数【def index(req):】
index.html
1
2
3
4
5
6
7
8
9
10
11
12
13
|
<!DOCTYPE html> <html lang = "en" > <head> <meta charset = "UTF-8" > <title>index< / title> < / head> <body> <form action = " " method=" post"> < input type = "text" name = "A" / > < input type = "submit" name = "b" value = "提交" / > < / form> < / body> < / html> |
上面就是FBV的使用。
CBV
将上述代码中的urls.py 修改为如下:
1
2
3
4
5
6
|
from mytest import views urlpatterns = [ # url(r‘^index/‘, views.index), url(r‘^index / ‘, views.Index.as_view()), ] |
注:url(r‘^index/‘, views.Index.as_view()), 是固定用法。
Django的url是将一个请求分配给可调用的函数的,而不是一个class。针对这个问题,class-based view提供了一个as_view()
静态方法(也就是类方法),调用这个方法,会创建一个类的实例,然后通过实例调用dispatch()
方法,dispatch()
方法会根据request的method的不同调用相应的方法来处理request(如get()
, post()
等)。
将上述代码中的views.py 修改为如下:
1
2
3
4
5
6
7
8
9
10
11
|
from django.views import View class Index(View): def get( self , req): print (‘method is :‘ + req.method) return render(req, ‘index.html‘) def post( self , req): print (‘method is :‘ + req.method) return render(req, ‘index.html‘) |
注:类要继承 View ,类中函数名必须小写。