Django基础之django分页
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:
<!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
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 %} <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <link rel="stylesheet" href="{% static 'bootstrap-3.3.0-dist/dist/css/bootstrap.min.css' %}"> </head> <body> <h1>数据展示</h1> <div class="container-fluid"> <div class="row"> <div class="col-md-6 col-md-offset-3"> <table class="table"> <thead> <tr> <th>id</th> <th>title</th> <th>价格</th> <th>性别</th> <th>出版日期</th> <th>出版社</th> <th>作者</th> <th>操作</th> </tr> </thead> <tbody> {% for book_obj in book_objs %} <tr> <td>{{ book_obj.pk }}</td> <td>{{ book_obj.title }}</td> <td>{{ book_obj.price }}</td> <td>{{ book_obj.get_sex_display }}</td> <td>{{ book_obj.publishDate|date:'Y-d-m' }}</td> <td>{{ book_obj.publish.name }}</td> <td> {% for author in book_obj.authors.all %} {{ author.name }} {% endfor %} </td> <td> <a class="btn btn-warning" href="{% url 'edit_book' book_obj.pk %}">编辑</a> <a class="btn btn-danger" href="{% url 'delete_book' book_obj.pk %}">删除</a> </td> </tr> {% endfor %} </tbody> </table> <ul class="pagination" id="pager"> {% if book_objs.has_previous %} <li class="previous"><a href="/show/?page={{ book_objs.previous_page_number }}">上一页</a></li> {% else %} <li class="previous disabled"><a href="javascript:void(0)">上一页</a></li> {% endif %} <!--{% for num in page_obj.page_range %}--> {% for num in pageRange %} {% if num == current_page_num %} <li class="item active"><a href="/show/?page={{ num }}">{{ num }}</a></li> {% else %} <li class="item"><a href="/show/?page={{ num }}">{{ num }}</a></li> {% endif %} {% endfor %} {% if book_objs.has_next %} <li class="next"><a href="/show/?page={{ book_objs.next_page_number }}">下一页</a></li> {% else %} <li class="next disabled"><a href="#">下一页</a></li> {% endif %} </ul> </div> </div> </div> </body> <script src="{% static 'bootstrap-3.3.0-dist/dist/jQuery/jquery-3.1.1.js' %}"></script> <script src="{% static 'bootstrap-3.3.0-dist/dist/js/bootstrap.min.js' %}"></script> </html>
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('<nav aria-label="Page navigation"><ul class="pagination">') # 加首页 first_li = '<li><a href="/publisher_list/?page=1">首页</a></li>' page_html_list.append(first_li) # 加上一页 if current_page == 1: prev_li = '<li><a href="#"><span aria-hidden="true">«</span></a></li>' else: prev_li = '<li><a href="/publisher_list/?page={}"><span aria-hidden="true">«</span></a></li>'.format(current_page - 1) page_html_list.append(prev_li) for i in range(page_start, page_end + 1): if i == current_page: li_tag = '<li class="active"><a href="/publisher_list/?page={0}">{0}</a></li>'.format(i) else: li_tag = '<li><a href="/publisher_list/?page={0}">{0}</a></li>'.format(i) page_html_list.append(li_tag) # 加下一页 if current_page == total_page: next_li = '<li><a href="#"><span aria-hidden="true">»</span></a></li>' else: next_li = '<li><a href="/publisher_list/?page={}"><span aria-hidden="true">»</span></a></li>'.format(current_page + 1) page_html_list.append(next_li) # 加尾页 page_end_li = '<li><a href="/publisher_list/?page={}">尾页</a></li>'.format(total_page) page_html_list.append(page_end_li) page_html_list.append('</ul></nav>') 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('<nav aria-label="Page navigation"><ul class="pagination">') # 加首页 first_li = '<li><a href="{}?page=1">首页</a></li>'.format(self.base_url) page_html_list.append(first_li) # 加上一页 if self.current_page == 1: prev_li = '<li><a href="#"><span aria-hidden="true">«</span></a></li>' else: prev_li = '<li><a href="{}?page={}"><span aria-hidden="true">«</span></a></li>'.format( self.base_url, self.current_page - 1) page_html_list.append(prev_li) for i in range(page_start, page_end + 1): if i == self.current_page: li_tag = '<li class="active"><a href="{0}?page={1}">{1}</a></li>'.format(self.base_url, i) else: li_tag = '<li><a href="{0}?page={1}">{1}</a></li>'.format(self.base_url, i) page_html_list.append(li_tag) # 加下一页 if self.current_page == self.total_page: next_li = '<li><a href="#"><span aria-hidden="true">»</span></a></li>' else: next_li = '<li><a href="{}?page={}"><span aria-hidden="true">»</span></a></li>'.format( self.base_url, self.current_page + 1) page_html_list.append(next_li) # 加尾页 page_end_li = '<li><a href="{}?page={}">尾页</a></li>'.format(self.base_url, self.total_page) page_html_list.append(page_end_li) page_html_list.append('</ul></nav>') 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})
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title></title> </head> <body> <ul> {% for item in posts %} <li>{{ item }}</li> {% endfor %} </ul> <div class="pagination"> <span class="step-links"> {% if posts.has_previous %} <a href="?p={{ posts.previous_page_number }}">Previous</a> {% endif %} <span class="current"> Page {{ posts.number }} of {{ posts.paginator.num_pages }}. </span> {% if posts.has_next %} <a href="?p={{ posts.next_page_number }}">Next</a> {% endif %} </span> </div> </body> </html>
