分页器

批量插入

def ab_pl(request):
    # 先给Book插入一万条数据
    # for i in range(10000):
    #     models.Book.objects.create(title='第%s本书'%i)
    # # 再将所有的数据查询并展示到前端页面
    book_queryset = models.Book.objects.all()

    # 批量插入
    # book_list = []
    # for i in range(100000):
    #     book_obj = models.Book(title='第%s本书'%i)
    #     book_list.append(book_obj)
    # models.Book.objects.bulk_create(book_list)
    """
    当你想要批量插入数据的时候 使用orm给你提供的bulk_create能够大大的减少操作时间
    :param request: 
    :return: 
    """
    return render(request,'ab_pl.html',locals())

 

分页器推导

总数据100 每页展示10 需要10
总数据101 每页展示10 需要11
总数据99 每页展示10 需要10

 

代码

    book_list = models.Book.objects.all()

    # 想访问哪一页
    current_page = request.GET.get('page',1)  # 如果获取不到当前页码 就展示第一页
    # 数据类型转换
    try:
        current_page = int(current_page)
    except Exception:
        current_page = 1
    # 每页展示多少条
    per_page_num = 10
    # 起始位置
    start_page = (current_page - 1) * per_page_num
    # 终止位置
    end_page = current_page * per_page_num

    # 计算出到底需要多少页
    all_count = book_list.count()

    page_count, more = divmod(all_count, per_page_num)
    if more:
        page_count += 1

    page_html = ''
    xxx = current_page
    if current_page < 6:
        current_page = 6
    for i in range(current_page-5,current_page+6):
        if xxx == i:
            page_html += '<li class="active"><a href="?page=%s">%s</a></li>'%(i,i)
        else:
            page_html += '<li><a href="?page=%s">%s</a></li>'%(i,i)



    book_queryset =  book_list[start_page:end_page]
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

下面需要研究current_page、per_page_num、start_page、end_page四个参数之间的数据关系
per_page_num = 10
current_page start_page end_page
1 0 10
2 10 20
3 20 30
4 30 40

per_page_num = 5
current_page start_page end_page
1 0 5
2 5 10
3 10 15
4 15 20
可以很明显的看出规律
start_page = (current_page - 1) * per_page_num
end_page = current_page* per_page_num

　　此时的分页器功能并不完善，只需要知道内部逻辑即可

自定义分页器的拷贝及使用

class Pagination(object):
    def __init__(self, current_page, all_count, 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 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
 
        # 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 = []
        # 添加前面的nav和ul标签
        page_html_list.append('''
                    <nav aria-label='Page navigation>'
                    <ul class='pagination'>
                ''')
        first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
        page_html_list.append(first_page)
 
        if self.current_page <= 1:
            prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
        else:
            prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)
 
        page_html_list.append(prev_page)
 
        for i in range(pager_start, pager_end):
            if i == self.current_page:
                temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
            else:
                temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
            page_html_list.append(temp)
 
        if self.current_page >= self.all_pager:
            next_page = '<li class="disabled"><a href="#">下一页</a></li>'
        else:
            next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
        page_html_list.append(next_page)
 
        last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
        page_html_list.append(last_page)
        # 尾部添加标签
        page_html_list.append('''
                                           </nav>
                                           </ul>
                                       ''')
        return ''.join(page_html_list)

　　

后端

from app02 import models as ap2_models

from app02.utills.gongju import Pagination

def burster(request):

# 自定义分页器的使用
    book_list = ap2_models.Burster.objects.all()
    current_page = request.GET.get('page',1)  # 如果获取不到当前页码 就展示第一页
    # # 计算出到底需要多少页
    all_count = book_list.count()
    fenyeqi = Pagination(current_page=current_page, all_count=all_count)
    page_queryset = book_list[fenyeqi.start:fenyeqi.end]
    return render(request, "burster.html",locals())

前端　　

 

{% for datum in page_queryset %}
    <p>{{ datum.data }}</p>
    <nav aria-label="Page navigation"></nav>
{% endfor %}

{{ fenyeqi.page_html|safe }}