Django基礎之django分頁

時間  2020-06-17
標籤 django 基礎 分頁 欄目 Python 简体版
原文   原文鏈接

1、Django的內置分頁器（paginator）

　　view

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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):

    '''
    批量導入數據:

    Booklist=[]
    for i in range(100):
        Booklist.append(Book(title="book"+str(i),price=30+i*i))
    Book.objects.bulk_create(Booklist)
    '''

    '''
分頁器的使用:

    book_list=Book.objects.all()

    paginator = Paginator(book_list, 10)

    print("count:",paginator.count)           #數據總數
    print("num_pages",paginator.num_pages)    #總頁數
    print("page_range",paginator.page_range)  #頁碼的列表



    page1=paginator.page(1) #第1頁的page對象
    for i in page1:         #遍歷第1頁的全部數據對象
        print(i)

    print(page1.object_list) #第1頁的全部數據


    page2=paginator.page(2)

    print(page2.has_next())            #是否有下一頁
    print(page2.next_page_number())    #下一頁的頁碼
    print(page2.has_previous())        #是否有上一頁
    print(page2.previous_page_number()) #上一頁的頁碼



    # 拋錯
    #page=paginator.page(12)   # error:EmptyPage 超過頁碼範圍

    #page=paginator.page("z")   # error:PageNotAnInteger 非法頁碼值
　　
    #page = page_obj.page(-1)  #That page number is less than 1 ，也是EmptyPage的錯誤，頁碼不能爲負數，最少也是1
    '''


    book_list=Book.objects.all()

    paginator = Paginator(book_list, 10) #按照每頁顯示10條來計算
    page = request.GET.get('page',1)  #未來訪問的url是這樣的 http://127.0.0.1:8000/路徑/?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})

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　　index.html:

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<!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>分頁器</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 }}">上一頁</a></li>
                 {% else %}
                    <li class="previous disabled"><a href="#">上一頁</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 }}">下一頁</a></li>
                 {% else %}
                    <li class="next disabled"><a href="#">下一頁</a></li>
                 {% endif %}

            </ul>
</div>


</body>
</html>

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　　擴展

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from django.core.paginator import Paginator,PageNotAnInteger,EmptyPage
def show(request):

    book_objs = models.Book.objects.all()
    page_obj = Paginator(book_objs,1)
    print('數據總數',page_obj.count)
    print('總頁數',page_obj.num_pages)
    print('頁碼列表',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:  #擴展，若是總的頁碼數大於了11，咱們就不把全部的頁碼數顯示出來了，只顯示其中11個頁面，當前頁左邊5個，右邊5個
        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})

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　　show.htmljavascript

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{% 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>數據展現</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>價格</th>
                        <th>性別</th>
                        <th>出版日期</th>
                        <th>出版社</th>
                        <th>做者</th>
                        <th>操做</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  %}">編輯</a>
                                <a class="btn btn-danger" href="{% url 'delete_book' book_obj.pk  %}">刪除</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 }}">上一頁</a></li>
                {% else %}
                <li class="previous disabled"><a href="javascript:void(0)">上一頁</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 }}">下一頁</a></li>
                 {% else %}
                    <li class="next disabled"><a href="#">下一頁</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>

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　　model.py文件內容：css

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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

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2、自定義分頁

　　當數據庫中數據有不少，咱們一般會在前端頁面作分頁展現。html

　　分頁的數據能夠在前端頁面實現，也能夠在後端實現分頁。前端

　　後端實現分頁的原理就是每次只請求一頁數據。java

　　準備工做jquery

　　咱們使用腳本批量建立一些測試數據（將下面的代碼保存到bulk_create.py文件中放到Django項目的根目錄，直接執行便可。）：git

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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，注意寫法

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　　看下面幾個版本的分頁：數據庫

img

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def publisher_list(request):
    # 從URL中取當前訪問的頁碼數
    try:
        current_page = int(request.GET.get('page'))
    except Exception as e:
        # 取不到或者頁碼數不是數字都默認展現第1頁
        current_page = 1
    # 總數據量
    total_count = models.Publisher.objects.count()
    # 定義每頁顯示多少條數據
    per_page = 10
    # 計算出總頁碼數
    total_page, more = divmod(total_count, per_page)
    if more:
        total_page += 1
    # 定義頁面上最多顯示多少頁碼(爲了左右對稱，通常設爲奇數)
    max_show = 11
    half_show = max_show // 2
    # 計算一下頁面顯示的頁碼範圍
    if total_page <= max_show:  # 總頁碼數小於最大顯示頁碼數
        page_start = 1
        page_end = total_page
    elif current_page + half_show >= total_page:  # 右邊越界
        page_end = total_page
        page_start = total_page - max_show
    elif current_page - half_show <= 1:  # 左邊越界
        page_start = 1
        page_end = max_show
    else:  # 正常頁碼區間
        page_start = current_page - half_show
        page_end = current_page + half_show
    # 數據索引發始位置
    data_start = (current_page-1) * per_page
    data_end = current_page * per_page

    publisher_list = models.Publisher.objects.all()[data_start:data_end]

    # 生成頁面上顯示的頁碼
    page_html_list = []
    page_html_list.append('<nav aria-label="Page navigation"><ul class="pagination">')
    # 加首頁
    first_li = '<li><a href="/publisher_list/?page=1">首頁</a></li>'
    page_html_list.append(first_li)
    # 加上一頁
    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)
    # 加下一頁
    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)
    # 加尾頁
    page_end_li = '<li><a href="/publisher_list/?page={}">尾頁</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})

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img

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class Pagination(object):
    """自定義分頁（Bootstrap版）"""
    def __init__(self, current_page, total_count, base_url, per_page=10, max_show=11):
        """
        :param current_page: 當前請求的頁碼
        :param total_count: 總數據量
        :param base_url: 請求的URL
        :param per_page: 每頁顯示的數據量，默認值爲10
        :param max_show: 頁面上最多顯示多少個頁碼，默認值爲11
        """
        try:
            self.current_page = int(current_page)
        except Exception as e:
            # 取不到或者頁碼數不是數字都默認展現第1頁
            self.current_page = 1
        # 定義每頁顯示多少條數據
        self.per_page = per_page
        # 計算出總頁碼數
        total_page, more = divmod(total_count, per_page)
        if more:
            total_page += 1
        self.total_page = total_page
        # 定義頁面上最多顯示多少頁碼(爲了左右對稱，通常設爲奇數)
        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):
        # 計算一下頁面顯示的頁碼範圍
        if self.total_page <= self.max_show:  # 總頁碼數小於最大顯示頁碼數
            page_start = 1
            page_end = self.total_page
        elif self.current_page + self.half_show >= self.total_page:  # 右邊越界
            page_end = self.total_page
            page_start = self.total_page - self.max_show
        elif self.current_page - self.half_show <= 1:  # 左邊越界
            page_start = 1
            page_end = self.max_show
        else:  # 正常頁碼區間
            page_start = self.current_page - self.half_show
            page_end = self.current_page + self.half_show
        # 生成頁面上顯示的頁碼
        page_html_list = []
        page_html_list.append('<nav aria-label="Page navigation"><ul class="pagination">')
        # 加首頁
        first_li = '<li><a href="{}?page=1">首頁</a></li>'.format(self.base_url)
        page_html_list.append(first_li)
        # 加上一頁
        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)
        # 加下一頁
        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)
        # 加尾頁
        page_end_li = '<li><a href="{}?page={}">尾頁</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)

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img

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def publisher_list(request):
    # 從URL中取當前訪問的頁碼數
    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})

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　　再來一版django內置分頁器的分頁django

img

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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: 每頁顯示條目數量
    # count:    數據總個數
    # num_pages:總頁數
    # page_range:總頁數的索引範圍，如: (1,10),(1,200)
    # page:     page對象
    try:
        posts = paginator.page(current_page)
        # has_next              是否有下一頁
        # next_page_number      下一頁頁碼
        # has_previous          是否有上一頁
        # previous_page_number  上一頁頁碼
        # object_list           分頁以後的數據列表
        # number                當前頁
        # paginator             paginator對象
    except PageNotAnInteger:
        posts = paginator.page(1)
    except EmptyPage:
        posts = paginator.page(paginator.num_pages)
    return render(request, 'index.html', {'posts': posts})

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img

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<!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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