分页

	分页器:
		-干啥的?数据量大的话,可以分页获取,查看
		基本写法:
			后端:
				-总数据拿出来
				-生成分页器Paginator对象(对象里有属性和方法)
				-生成当前页的对象,current_page=paginator.page(当前页码)
				-取出前台传过来的页码,current_page_num = int(request.GET.get('page'))
					-需要有异常捕获
					-捕获到,把当前页码设置成第一页
			
			
			前端:
				-for循环总页列表
				-点某一页,跳到指定页码,<li><a href="/index/?page={{ foo }}">{{ foo }}</a></li>
				
				-上一页,下一页的处理:需要有判断,判断是否有上一页,下一页
		-终极版:
			#判断总页码数是否大于11,不大于11,走else:把总页码数,赋给page_range(前端循环页码列表,循环的就是page_range)
			if paginator.num_pages >11:
				# 当前页码数-5大于1的时候,page_range应该是,page_range就是1到11页?
				if current_page_num-5<1:
					page_range=range(1,12)
				elif current_page_num+5>paginator.num_pages:
					# 当前页码数+5大于总页码数,总页码-10,到总页码+1之间
					page_range=range(paginator.num_pages-10,paginator.num_pages+1)
				else:
					#其他情况,左5,右6推算,也就是:range(current_page_num - 5, current_page_num + 6)
					page_range = range(current_page_num - 5, current_page_num + 6)
			else:
				#小于11,有多少页,就显示多少页
				page_range=paginator.page_range
			
		
	批量插入输入:
		-models.Book.objects.bulk_create(ll)

代码示范

from django.shortcuts import render, HttpResponse

# Create your views here.
from django.core.paginator import Paginator, EmptyPage
from app01 import models


# def index(request):
#     # 初级方法
#     # for i in range(100):
#     #     models.Book.objects.create(name='图书%s'%i,price=10+i)
#     # 进阶方法(批量插入)
#     # 先造成100本书,放到列表中
#     # ll=[]
#     # for i in range(100):
#     #     ll.append(models.Book(name='图书%s'%i,price=10+i))
#     # # 批量插入,两个参数,第一个是对象列表,第二个是一次插入的数据量,不填,默认一次全插入
#     # models.Book.objects.bulk_create(ll)
#
#     # 查询所有图书
#     book_list=models.Book.objects.all()
#     # 分页器--类
#     # 实例化产生一个对象
#     # 两个参数:object_list:对象列表, per_page:每页显示的条数
#     paginator=Paginator(book_list,10)
#     # 对象内的属性
#     # 数据总条数100条
#     # print(paginator.count)
#     # # 总页数  10页
#     # print(paginator.num_pages)
#     # # 页码数的列表
#     # print(paginator.page_range)
#     # # 取到第 x 页 ,返回一个Page对象
#     # current_page=paginator.page(5)
#     # # 当前页码内所有的数据
#     # print(current_page.object_list)
#     # # 是否有下一页
#     # print(current_page.has_next())
#     # # 是否有上一页
#     # print(current_page.has_previous())
#     # # 下一页页码数
#     # print(current_page.next_page_number())
#     # # 上一页的页码数
#     # print(current_page.previous_page_number())
#
#
#     return render(request,'index.html',locals())

# def index(request):
#     book_list = models.Book.objects.all()
#
#     paginator = Paginator(book_list, 3)
#     # 当前页码
#     try:
#         current_page_num = int(request.GET.get('page'))
#         current_page = paginator.page(current_page_num)
#         # 当前页码所有数据
#         print(current_page.object_list)
#         # 即可以循环current_page.object_list,又可以循环当前页的对象
#         # for item in current_page:
#         #     print(item.name)
#     # except EmptyPage as e:
#     #     # 捕获异常后,跳到第一页
#     #     current_page_num = 1
#     #     current_page = paginator.page(current_page_num)
#     except Exception as e:
#         current_page_num = 1
#         current_page = paginator.page(current_page_num)
#
#     return render(request, 'index.html', locals())

def index(request):
    book_list = models.Book.objects.all()
    paginator = Paginator(book_list, 3)
    # 如果页码数多,让它显示前5,后5,中间是当前在的页码
    try:

        current_page_num = int(request.GET.get('page'))
        current_page = paginator.page(current_page_num)
        print(current_page.object_list)
        # 总页码数,大于11的时候
        if paginator.num_pages >11:
            # 当前页码数-5大于1的时候,page_range应该是?
            if current_page_num-5<1:
                page_range=range(1,12)
            elif current_page_num+5>paginator.num_pages:
                #     当前页码数+5大于总页码数,总页码数往前推11个
                page_range=range(paginator.num_pages-10,paginator.num_pages+1)
            else:
                page_range = range(current_page_num - 5, current_page_num + 6)
        else:
            #小于11,有多少页,就显示多少页
            page_range=paginator.page_range
    except Exception as e:
        current_page_num = 1
        current_page = paginator.page(current_page_num)

    return render(request, 'index_next.html', locals())