一、Django的内置分页器（paginator）
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 超过页码范围
#page=paginator.page("z") # error:PageNotAnInteger 非法页码值
#page = page_obj.page(-1) #That page number is less than 1 ，也是EmptyPage的错误，页码不能为负数，最少也是1
'''
book_list=Book.objects.all()
paginator = Paginator(book_list, 10) #按照每页显示10条来计算
page = request.GET.get('page',1) #将来访问的url是这样的 http://127.0.0.1:8000/路径/?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})index.html:
Title
分页器
{% for book in book_list %}
- {{ book.title }} -----{{ book.price }}
{% endfor %}
扩展
from django.core.paginator import Paginator,PageNotAnInteger,EmptyPage
def show(request):
book_objs = models.Book.objects.all()
page_obj = Paginator(book_objs,1)
print('数据总数',page_obj.count)
print('总页数',page_obj.num_pages)
print('页码列表',page_obj.page_range)
page1 = page_obj.page(1)
for i in page1:
print(i)
print(page1.object_list)
page2 = page_obj.page(2)
print(page2.has_previous())
print(page2.has_next())
print(page2.next_page_number())
print(page2.previous_page_number())
# page = page_obj.page(-1)
page_num = request.GET.get('page',1)
try:
current_page_num = int(page_num)
page_num_data = page_obj.page(current_page_num)
except PageNotAnInteger:
current_page_num = 1
page_num_data = page_obj.page(current_page_num)
except EmptyPage:
current_page_num = page_obj.num_pages
page_num_data = page_obj.page(current_page_num)
except Exception:
current_page_num = 1
page_num_data = page_obj.page(current_page_num)
if page_obj.num_pages > 11: #扩展，如果总的页码数大于了11，我们就不把所有的页码数显示出来了，只显示其中11个页面，当前页左边5个，右边5个
if current_page_num - 5 < 1:
pageRange = range(1,12)
elif current_page_num + 5 > page_obj.num_pages:
pageRange = range(page_obj.num_pages-10,page_obj.num_pages+1)
else:
pageRange = range(current_page_num - 5,current_page_num + 6)
else:
pageRange = page_obj.page_range
book_objs = page_num_data
return render(request,'show.html',{'book_objs':book_objs,'current_page_num':current_page_num,'page_obj':page_obj,'pageRange':pageRange})show.html
{% load static %}
Title
数据展示
id
title
价格
性别
出版日期
出版社
作者
操作
{% for book_obj in book_objs %}
{{ book_obj.pk }}
{{ book_obj.title }}
{{ book_obj.price }}
{{ book_obj.get_sex_display }}
{{ book_obj.publishDate|date:'Y-d-m' }}
{{ book_obj.publish.name }}
{% for author in book_obj.authors.all %}
{{ author.name }}
{% endfor %}
编辑
删除
{% endfor %}
model.py文件内容：
from django.db import models
# Create your models here.
class Author(models.Model):
nid = models.AutoField(primary_key=True)
name=models.CharField( max_length=32)
age=models.IntegerField()
authorDetail=models.OneToOneField(to="AuthorDetail",to_field="nid")
def __str__(self):
return self.name
class AuthorDetail(models.Model):
nid = models.AutoField(primary_key=True)
birthday=models.DateField()
telephone=models.BigIntegerField()
addr=models.CharField( max_length=64)
class Publish(models.Model):
nid = models.AutoField(primary_key=True)
name=models.CharField( max_length=32)
city=models.CharField( max_length=32)
email=models.EmailField()
def __str__(self):
return self.name
class Book(models.Model):
nid = models.AutoField(primary_key=True)
title = models.CharField( max_length=32)
publishDate=models.DateField()
price=models.DecimalField(max_digits=5,decimal_places=2)
publish=models.ForeignKey(to="Publish",to_field="nid")
authors=models.ManyToManyField(to='Author',)
def __str__(self):
return self.title二、自定义分页
当数据库中数据有很多，我们通常会在前端页面做分页展示。
分页的数据可以在前端页面实现，也可以在后端实现分页。
后端实现分页的原理就是每次只请求一页数据。
准备工作
我们使用脚本批量创建一些测试数据（将下面的代码保存到bulk_create.py文件中放到Django项目的根目录，直接执行即可。）：
import os
if __name__ == "__main__":
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "about_orm.settings")
import django
django.setup()
from app01 import models
bulk_obj = (models.Publisher(name='第{}出版社'.format(i)) for i in range(300))
models.Publisher.objects.bulk_create(bulk_obj) #批量添加，注意写法看下面几个版本的分页：
def publisher_list(request):
# 从URL中取当前访问的页码数
try:
current_page = int(request.GET.get('page'))
except Exception as e:
# 取不到或者页码数不是数字都默认展示第1页
current_page = 1
# 总数据量
total_count = models.Publisher.objects.count()
# 定义每页显示多少条数据
per_page = 10
# 计算出总页码数
total_page, more = divmod(total_count, per_page)
if more:
total_page += 1
# 定义页面上最多显示多少页码(为了左右对称，一般设为奇数)
max_show = 11
half_show = max_show // 2
# 计算一下页面显示的页码范围
if total_page <= max_show: # 总页码数小于最大显示页码数
page_start = 1
page_end = total_page
elif current_page + half_show >= total_page: # 右边越界
page_end = total_page
page_start = total_page - max_show
elif current_page - half_show <= 1: # 左边越界
page_start = 1
page_end = max_show
else: # 正常页码区间
page_start = current_page - half_show
page_end = current_page + half_show
# 数据索引起始位置
data_start = (current_page-1) * per_page
data_end = current_page * per_page
publisher_list = models.Publisher.objects.all()[data_start:data_end]
# 生成页面上显示的页码
page_html_list = []
page_html_list.append('')
page_html = "".join(page_html_list)
return render(request, "publisher_list.html", {"publisher_list": publisher_list, "page_html": page_html})class Pagination(object):
"""自定义分页（Bootstrap版）"""
def __init__(self, current_page, total_count, base_url, per_page=10, max_show=11):
"""
:param current_page: 当前请求的页码
:param total_count: 总数据量
:param base_url: 请求的URL
:param per_page: 每页显示的数据量，默认值为10
:param max_show: 页面上最多显示多少个页码，默认值为11
"""
try:
self.current_page = int(current_page)
except Exception as e:
# 取不到或者页码数不是数字都默认展示第1页
self.current_page = 1
# 定义每页显示多少条数据
self.per_page = per_page
# 计算出总页码数
total_page, more = divmod(total_count, per_page)
if more:
total_page += 1
self.total_page = total_page
# 定义页面上最多显示多少页码(为了左右对称，一般设为奇数)
self.max_show = max_show
self.half_show = max_show // 2
self.base_url = base_url
@property
def start(self):
return (self.current_page-1) * self.per_page
@property
def end(self):
return self.current_page * self.per_page
def page_html(self):
# 计算一下页面显示的页码范围
if self.total_page <= self.max_show: # 总页码数小于最大显示页码数
page_start = 1
page_end = self.total_page
elif self.current_page + self.half_show >= self.total_page: # 右边越界
page_end = self.total_page
page_start = self.total_page - self.max_show
elif self.current_page - self.half_show <= 1: # 左边越界
page_start = 1
page_end = self.max_show
else: # 正常页码区间
page_start = self.current_page - self.half_show
page_end = self.current_page + self.half_show
# 生成页面上显示的页码
page_html_list = []
page_html_list.append('')
return "".join(page_html_list)def publisher_list(request):
# 从URL中取当前访问的页码数
current_page = int(request.GET.get('page'))
# 比len(models.Publisher.objects.all())更高效
total_count = models.Publisher.objects.count()
page_obj = Pagination(current_page, total_count, request.path_info)
data = models.Publisher.objects.all()[page_obj.start:page_obj.end]
page_html = page_obj.page_html()
return render(request, "publisher_list.html", {"publisher_list": data, "page_html": page_html})再来一版django内置分页器的分页
from django.shortcuts import render
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
L = []
for i in range(999):
L.append(i)
def index(request):
current_page = request.GET.get('p')
paginator = Paginator(L, 10)
# per_page: 每页显示条目数量
# count: 数据总个数
# num_pages:总页数
# page_range:总页数的索引范围，如: (1,10),(1,200)
# page: page对象
try:
posts = paginator.page(current_page)
# has_next 是否有下一页
# next_page_number 下一页页码
# has_previous 是否有上一页
# previous_page_number 上一页页码
# object_list 分页之后的数据列表
# number 当前页
# paginator paginator对象
except PageNotAnInteger:
posts = paginator.page(1)
except EmptyPage:
posts = paginator.page(paginator.num_pages)
return render(request, 'index.html', {'posts': posts})
{% for item in posts %}
- {{ item }}
{% endfor %}