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

    #page=paginator.page("z")   # error:PageNotAnInteger

    '''

    book_list=Book.objects.all()

    paginator = Paginator(book_list, 10)

    page = request.GET.get('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

def index(request):

    book_list=Book.objects.all()

    paginator = Paginator(book_list, 15)

    page = request.GET.get('page',1)

    currentPage=int(page)

    #  如果页数十分多时，换另外一种显示方式

    if paginator.num_pages>11:

        if currentPage-5<1:

            pageRange=range(1,11)

        elif currentPage+5>paginator.num_pages:

            pageRange=range(currentPage-5,paginator.num_pages+1)

        else:

            pageRange=range(currentPage-5,currentPage+5)

    else:

        pageRange=paginator.page_range

    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",locals())

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">&laquo;</span></a></li>'

    else:

        prev_li = '<li><a href="/publisher_list/?page={}"><span 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="/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">&raquo;</span></a></li>'

    else:

        next_li = '<li><a href="/publisher_list/?page={}"><span 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="/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})
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">&laquo;</span></a></li>'

    else:

        prev_li = '<li><a href="/publisher_list/?page={}"><span 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="/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">&raquo;</span></a></li>'

    else:

        next_li = '<li><a href="/publisher_list/?page={}"><span 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="/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">&laquo;</span></a></li>'

        else:

            prev_li = '<li><a href="{}?page={}"><span 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="{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">&raquo;</span></a></li>'

        else:

            next_li = '<li><a href="{}?page={}"><span 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="{}?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)
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">&laquo;</span></a></li>'

        else:

            prev_li = '<li><a href="{}?page={}"><span 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="{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">&raquo;</span></a></li>'

        else:

            next_li = '<li><a href="{}?page={}"><span 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="{}?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})
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})
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>
<!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>
 
 
 
 

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