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
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