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flask如何实现内容分页功能

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flask如何实现内容分页功能

2022-05-2612:04:15评论

在web开发中，分页是必不可少的功能，Flask实现展示内容的分页也非常简单，这里通过实例来学习一下Flask如何为网站分页。

首先，自定义一个分页工具类page_utils：

  1. from urllib import urlencode
  2. class Pagination(object):
  3.     def __init__(self, current_page, total_count, base_url, params, per_page_count=10, max_pager_count=11):
  4.             current_page = int(current_page)
  5.         except Exception as e:
  6.             current_page = 1
  7.         if current_page <=0:
  8.             current_page = 1
  9.         self.current_page = current_page
  10.         self.total_count = total_count
  11.         self.per_page_count = per_page_count
  12.         max_page_num, div = divmod(total_count, per_page_count)
  13.         if div:
  14.             max_page_num += 1
  15.         self.max_page_num = max_page_num
  16.         self.max_pager_count = max_pager_count
  17.         self.half_max_pager_count = int((max_pager_count - 1) / 2)
  18.         self.base_url = base_url
  19.         import copy
  20.         params = copy.deepcopy(params)
  21.         get_dict = params.to_dict() 
  22.         self.params = get_dict
  23.     @property
  24.     def start(self):
  25.         return (self.current_page - 1) * self.per_page_count
  26.     @property
  27.     def end(self):
  28.         return self.current_page * self.per_page_count 
  29.     def page_html(self):
  30.         if self.max_page_num <= self.max_pager_count:
  31.             pager_start = 1
  32.             pager_end = self.max_page_num
  33.         # 如果总页数 > 11
  34.         else:
  35.             if self.current_page <= self.half_max_pager_count:
  36.                 pager_start = 1
  37.                 pager_end = self.max_pager_count
  38.             else:
  39.                 if (self.current_page + self.half_max_pager_count) > self.max_page_num:
  40.                     pager_end = self.max_page_num
  41.                     pager_start = self.max_page_num - self.max_pager_count + 1   #倒这数11个
  42.                 else:
  43.                     pager_start = self.current_page - self.half_max_pager_count
  44.                     pager_end = self.current_page + self.half_max_pager_count
  45.         page_html_list = []
  46.         self.params['page'] = 1
  47.         first_page = '<li><a href="%s?%s">首页</a></li>'.decode("utf-8") % (self.base_url,urlencode(self.params),)
  48.         page_html_list.append(first_page)
  49.         self.params["page"] = self.current_page - 1
  50.         if self.params["page"] < 1:
  51.             pervious_page = '<li class="disabled"><a href="%s?%s" aria-label="Previous">上一页</span></a></li>'.
  52.             decode("utf-8") % (self.base_url, urlencode(self.params))
  53.         else:
  54.             pervious_page = '<li><a href = "%s?%s" aria-label = "Previous" >上一页</span></a></li>'.decode("utf-8") % 
  55.             ( self.base_url, urlencode(self.params))
  56.         page_html_list.append(pervious_page)
  57.         # 中间页码
  58.         for i in range(pager_start, pager_end + 1):
  59.             self.params['page'] = i
  60.             if i == self.current_page:
  61.                 temp = '<li class="active"><a href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
  62.             else:
  63.                 temp = '<li><a href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
  64.             page_html_list.append(temp)
  65.         self.params["page"] = self.current_page + 1
  66.         if self.params["page"] > self.max_page_num:
  67.             self.params["page"] = self.current_page
  68.             next_page = '<li class="disabled"><a href = "%s?%s" aria-label = "Next">下一页</span></a></li >'.decode
  69.             ("utf-8") % (self.base_url, urlencode(self.params))
  70.         else:
  71.             next_page = '<li><a href = "%s?%s" aria-label = "Next">下一页</span></a></li>'.decode("utf-8") % 
  72.             (self.base_url, urlencode(self.params))
  73.         page_html_list.append(next_page)
  74.         self.params['page'] = self.max_page_num
  75.         last_page = '<li><a href="%s?%s">尾页</a></li>'.decode("utf-8") % (self.base_url, urlencode(self.params),)
  76.         page_html_list.append(last_page)
  77.         return ''.join(page_html_list)


自定义方法中的参数：


current_page——表示当前页。


total_count——表示数据总条数。


base_url——表示分页URL前缀，请求的前缀获取可以通过Flask的request.path方法，无需自己指定。


例如：我们的路由方法为@app.route('/test')，request.path方法即可获取/test。


params——表示请求传入的数据，params可以通过request.args动态获取。


例如：我们链接点击为：http://localhost:5000/test?page=10，此时request.args获取数据为ImmutableMultiDict([('page', u'10')])


per_page_count——指定每页显示数。


max_pager_count——指定页面最大显示页码


接着，我们使用一个测试方法来使用这个工具类，达到分页效果，test.py:


  1. from <a href="http://www.gaodaima.com/tag/flask" title="查看更多关于flask的文章" target="_blank">flask</a> import Flask, render_template, request
  2. from page_utils import Pagination
  3. app = Flask(__name__) 
  4. @app.route('/test')
  5. def test():
  6.     li = []
  7.     for i in range(1, 100):
  8.         li.append(i)
  9.     pager_obj = Pagination(request.args.get("page", 1), len(li), request.path, request.args, per_page_count=10)
  10.     print(request.path)
  11.     print(request.args)
  12.     index_list = li[pager_obj.start:pager_obj.end]
  13.     html = pager_obj.page_html()
  14.     return render_template("obj/test.html", index_list=index_list, html=html)
  15. if __name__ == '__main__':
  16.     app.run(debug=True)


在上面的程序中，li为我们要分页的对象，数组list，我们获取到这个list之后，把他用工具类中的起止方法包起来。


传递数据用包装后的list，这样就达到了需要哪一段数据我们传递哪一段的效果，包装的方法：index_list = li[pager_obj.start:pager_obj.end]


我们用一个HTML页面去显示它，分页样式不是重点，我们这里直接引入bootstrap封装好的分页效果，代码如下：


  1. <!DOCTYPE html>
  2. <html>
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6.     <link rel="stylesheet" href="{{%20url_for('static',%20filename='css/bootstrap.min.css')%20}}">
  7.     <style>
  8.         .container{
  9.             margin-top: 20px;
  10.     </style>
  11. </head>
  12. <body>
  13.     <div>
  14.         <div class="row " style="margin-top: 10px">
  15.                 <ul>
  16.                     {% for foo in index_list %}
  17.                         <li>{{ foo }}：这是列表内容~~</li>
  18.                     {% endfor %}
  19.                 </ul>
  20.                 <nav aria-label="Page navigation">
  21.                     <ul>
  22.                         {{ html|safe }}
  23.                     </ul>
  24.                 </nav>
  25.         </div>
  26.     </div>
  27. </body>
  28. </html>


这样一个分页的效果就做好了！


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