13.Django基础之django分页

King

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})

知识兔

index.html:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="https://zhishitu.com/" target="_blank"     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="https://zhishitu.com/" target="_blank" book_list.previous_page_number }}">上一页</a></li>
                 {% else %}
                    <li class="previous disabled"><a href="https://zhishitu.com/" target="_blank"
                 {% endif %}


                 {% for num in paginator.page_range %}

                     {% if num == currentPage %}
                       <li class="item active"><a href="https://zhishitu.com/" target="_blank" num }}">{{ num }}</a></li>
                     {% else %}
                       <li class="item"><a href="https://zhishitu.com/" target="_blank" num }}">{{ num }}</a></li>

                     {% endif %}
                 {% endfor %}



                 {% if book_list.has_next %}
                    <li class="next"><a href="https://zhishitu.com/" target="_blank" book_list.next_page_number }}">下一页</a></li>
                 {% else %}
                    <li class="next disabled"><a href="https://zhishitu.com/" target="_blank"
                 {% endif %}

            </ul>
</div>


</body>
</html>

知识兔

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})

知识兔

　　show.html

{% load static %}
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="https://zhishitu.com/" target="_blank" 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="https://zhishitu.com/" target="_blank" url 'edit_book' book_obj.pk  %}">编辑</a>
                                <a class="btn btn-danger" href="https://zhishitu.com/" target="_blank" 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="https://zhishitu.com/" target="_blank" book_objs.previous_page_number }}">上一页</a></li>
                {% else %}
                <li class="previous disabled"><a href="https://zhishitu.com/" target="_blank"
                {% endif %}
                <!--{% for num in page_obj.page_range %}-->
                {% for num in pageRange %}
                    {% if num == current_page_num %}
                     <li class="item active"><a href="https://zhishitu.com/" target="_blank" num }}">{{ num }}</a></li>
                    {% else %}
                       <li class="item"><a href="https://zhishitu.com/" target="_blank" num }}">{{ num }}</a></li>

                     {% endif %}

                {% endfor %}
                {% if book_objs.has_next %}
                    <li class="next"><a href="https://zhishitu.com/" target="_blank" book_objs.next_page_number }}">下一页</a></li>
                 {% else %}
                    <li class="next disabled"><a href="https://zhishitu.com/" target="_blank"
                 {% 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>

知识兔

　　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

知识兔

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

知识兔

　　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="https://zhishitu.com/" target="_blank"
    page_html_list.append(first_li)
    # 加上一页
    if current_page == 1:
        prev_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&laquo;</span></a></li>'
    else:
        prev_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&laquo;</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="https://zhishitu.com/" target="_blank"
        else:
            li_tag = '<li><a href="https://zhishitu.com/" target="_blank"
        page_html_list.append(li_tag)
    # 加下一页
    if current_page == total_page:
        next_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&raquo;</span></a></li>'
    else:
        next_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&raquo;</span></a></li>'.format(current_page + 1)
    page_html_list.append(next_li)
    # 加尾页
    page_end_li = '<li><a href="https://zhishitu.com/" target="_blank"
    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})

知识兔

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="https://zhishitu.com/" target="_blank"        page_html_list.append(first_li)        # 加上一页        if self.current_page == 1:            prev_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&laquo;</span></a></li>'        else:            prev_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&laquo;</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="https://zhishitu.com/" target="_blank" i)            else:                li_tag = '<li><a href="https://zhishitu.com/" target="_blank" i)            page_html_list.append(li_tag)        # 加下一页        if self.current_page == self.total_page:            next_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&raquo;</span></a></li>'        else:            next_li = '<li><a href="https://zhishitu.com/" target="_blank" aria-hidden="true">&raquo;</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="https://zhishitu.com/" target="_blank" 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 renderfrom django.core.paginator import Paginator, EmptyPage, PageNotAnIntegerL = []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="https://zhishitu.com/" target="_blank" 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="https://zhishitu.com/" target="_blank" posts.next_page_number }}">Next</a>          {% endif %}      </span></div></body></html>

计算机

2022年1月19日

13.Django基础之django分页

一、Django的内置分页器（paginator）

view

index.html:

扩展

二、自定义分页

热门标签

最新文章