Django之分页

一、Django的分页器（paginator）

1、批量导入数据

book_list = []
for i in range(100):
    book_obj = Book(title="Book_%s" % i, price=i * i)
    book_list.append(book_obj)
Book.objects.bulk_create(book_list)

2、分页用法

views.py文件内容:

from django.shortcuts import render,HttpResponse
from app01.models import *
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
def index(request):
    '''
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)       #每页显示10条数据
    page = request.GET.get('page',1)          #当前的所在的页数
    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文件内容：

    
    
    



    
分页器
    

        {% for book in book_list %}
             
{{ book.title }} -----{{ book.price }}
        {% endfor %}
     
    
                 {% if book_list.has_previous %}
                    
上一页
                 {% else %}
                    上一页
                 {% endif %}
                 {% for num in paginator.page_range %}
                     {% if num == currentPage %}
                       {{ num }}
                     {% else %}
                       
{{ num }}
                     {% endif %}
                 {% endfor %}
                 {% if book_list.has_next %}
                    
下一页
                 {% else %}
                    下一页
                 {% endif %}
            

3、对显示大量页码列表进行优化

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>30:
        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

"""
分页组件使用示例：
    obj = Pagination(request.GET.get('page',1),len(USER_LIST),request.path_info)
    page_user_list = USER_LIST[obj.start:obj.end]
    page_html = obj.page_html()
    return render(request,'index.html',{'users':page_user_list,'page_html':page_html})
"""
class Pagination(object):
    def __init__(self,current_page,all_count,base_url,per_page_num=2,pager_count=11):
        """
        封装分页相关数据
        :param current_page: 当前页
        :param all_count:    数据库中的数据总条数
        :param per_page_num: 每页显示的数据条数
        :param base_url: 分页中显示的URL前缀
        :param pager_count:  最多显示的页码个数
        """
        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1
        if current_page <1:
            current_page = 1
        self.current_page = current_page
        self.all_count = all_count
        self.per_page_num = per_page_num
        self.base_url = base_url
        # 总页码
        all_pager, tmp = divmod(all_count, per_page_num)
        if tmp:
            all_pager += 1
        self.all_pager = all_pager
        self.pager_count = pager_count
        self.pager_count_half = int((pager_count - 1) / 2)
    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_num
    @property
    def end(self):
        return self.current_page * self.per_page_num
    def page_html(self):
        # 如果总页码 < 11个：
        if self.all_pager <= self.pager_count:
            pager_start = 1
            pager_end = self.all_pager + 1
        # 总页码  > 11
        else:
            # 当前页如果<=页面上最多显示11/2个页码
            if self.current_page <= self.pager_count_half:
                pager_start = 1
                pager_end = self.pager_count + 1
            # 当前页大于5
            else:
                # 页码翻到最后
                if (self.current_page + self.pager_count_half) > self.all_pager:
                    pager_end = self.all_pager + 1
                    pager_start = self.all_pager - self.pager_count + 1
                else:
                    pager_start = self.current_page - self.pager_count_half
                    pager_end = self.current_page + self.pager_count_half + 1
        page_html_list = []
        first_page = '
首页
' % (self.base_url,1,)
        page_html_list.append(first_page)
        if self.current_page <= 1:
            prev_page = '
上一页
'
        else:
            prev_page = '
上一页
' % (self.base_url,self.current_page - 1,)
        page_html_list.append(prev_page)
        for i in range(pager_start, pager_end):
            if i == self.current_page:
                temp = '
%s
' % (self.base_url,i, i,)
            else:
                temp = '
%s
' % (self.base_url,i, i,)
            page_html_list.append(temp)
        if self.current_page >= self.all_pager:
            next_page = '
下一页
'
        else:
            next_page = '
下一页
' % (self.base_url,self.current_page + 1,)
        page_html_list.append(next_page)
        last_page = '
尾页
' % (self.base_url,self.all_pager,)
        page_html_list.append(last_page)
        return ''.join(page_html_list)