django 自定义分页类改善，适用于于条件查询等操作，提高灵活性

之前的一篇文章 http://blog.csdn.net/u011085172/article/details/71405043  里面写到的自定义分页类，因在代码中只能对数据库表进行all()方式的查询操作，

不能满足filter或者其他的条件查询，刚好今天碰到要用，于是改善了下代码：

class Pagination(object):      """分页基础类"""      """通过给的model和分页参数对相关model进行分页         Args:              from_name: 导入模块的 from后面的参数                 from {from_name} import model_name             mode_name: 需要导入的模块名                 from from_name import {model_name}             cur_page: 当前显示的是第几页             start_page_omit_symbol: 超出的页数使用怎么样的省略号(前)                 ... 2 3 4             end_page_omit_symbol: 超出的页数使用怎么样的省略号(后)                 1 2 3 4 ...             one_page_data_size: 每一页显示几行             show_page_item_len: 显示几个能点击的页数         Return:              pagination: dict                     pagination = {                          'objs': objs, # 需要显示model数据                         'all_obj_counts': all_obj_counts, # 一共多少行数据                         'start_pos': start_pos, # 数据分页开始的数据                          'end_pos': end_pos, # 数据分页结束的数据                          'all_page': all_page, # 一共有多少页                         'cur_page': cur_page, # 当前的页码                         'pre_page': pre_page, # 上一页的页码                         'next_page': next_page, # 下一页的页码                         'page_items': page_items, 能点击的页数                         'start_page_omit_symbol': start_page_omit_symbol, # 开始的省略号                         'end_page_omit_symbol': end_page_omit_symbol, # 结束的省略号                     }           Raise: None         """        def __init__(self,            from_name='',             model_name='',              cur_page=1,             start_page_omit_symbol = '...',              end_page_omit_symbol = '...',             one_page_data_size=1,              show_page_item_len=9,            classType = ''):          self.from_name = from_name        self.model_name = model_name        self.cur_page = cur_page        self.start_page_omit_symbol = start_page_omit_symbol        self.end_page_omit_symbol = end_page_omit_symbol        self.one_page_data_size = one_page_data_size        self.show_page_item_len = show_page_item_len        self.start_pos = (self.cur_page - 1) * self.one_page_data_size            self.end_pos = self.start_pos + self.one_page_data_size        self.classType = classType        # 如果没有输入导入模块需要的相关信息直接退出          if not self.from_name or not self.model_name:              return None        import_str = 'from {from_name} import {model_name}'.format(                                            from_name = self.from_name,                                            model_name = self.model_name)          # 导入模块          exec import_str        def getObjs(self):        # 查找需要的model数据          find_objs_str = ('{model_name}.objects.all()'                           '[{start_pos}:{end_pos}]'.format(                                                 model_name = self.model_name,                                                 start_pos = self.start_pos,                                                 end_pos = self.end_pos))        return eval(find_objs_str)        def getTotalPage(self):        # 计算总共的页数          find_objs_count_str = '{model_name}.objects.count()'.format(                                                 model_name = self.model_name)          all_obj_counts = eval(find_objs_count_str)        return all_obj_counts         def create_pagination(self):                              objs = self.getObjs()        all_obj_counts = self.getTotalPage()            all_page =  all_obj_counts / self.one_page_data_size         remain_obj = all_obj_counts % self.one_page_data_size          if remain_obj > 0:              all_page += 1             # 限制当前页不能小于1和并且大于总页数          cur_page = 1 if self.cur_page < 1 else self.cur_page          cur_page = all_page if self.cur_page > all_page else self.cur_page             # 获得显示页数的最小页          start_page = self.cur_page - self.show_page_item_len / 2          if start_page > all_page - self.show_page_item_len:              start_page = all_page - self.show_page_item_len + 1          start_page = 1 if start_page < 1 else start_page             # 获得显示页数的最大页          end_page = self.cur_page + self.show_page_item_len / 2          end_page = all_page if end_page > all_page else end_page          if end_page < self.show_page_item_len and all_page > self.show_page_item_len:              end_page = self.show_page_item_len             # 获得上一页          pre_page = self.cur_page - 1          pre_page = 1 if pre_page < 1 else pre_page             # 获得下一页          next_page = self.cur_page + 1          next_page = all_page if next_page > all_page else next_page             # 处理省略符，是否显示          if start_page <= 1:              self.start_page_omit_symbol = ''                     if end_page >= all_page:              self.end_page_omit_symbol = ''             # 创建能点击的展示页码          page_items = range(start_page, end_page + 1)             pagination = {              'objs': objs,              'all_obj_counts': all_obj_counts,              'start_pos': self.start_pos,              'end_pos': self.end_pos,              'all_page': all_page,              'cur_page': self.cur_page,              'pre_page': pre_page,              'next_page': next_page,              'page_items': page_items,              'start_page_omit_symbol': self.start_page_omit_symbol,              'end_page_omit_symbol': self.end_page_omit_symbol,          }             return pagination

这个类作为基础类，在原先的基础上，把设计到数据库操作的代码封装到函数中去，便于子类对这些函数的重写

例如以下代码，示例条件查询的写法：

class AllAbstPagination(Pagination):    '''获取所有文档摘要的类，从基础类继承        重写getObjs函数    '''    def getObjs(self):        # 查找需要的model数据          find_objs_str = ('{model_name}.objects.all()'                           '[{start_pos}:{end_pos}]'.format(                                                 model_name = self.model_name,                                                 start_pos = self.start_pos,                                                 end_pos = self.end_pos))        objs = []        for file in eval(find_objs_str):            objs.append(file.get_abstract())        return objsclass ClassAbstPagination(Pagination):    '''获取指定分类下文档摘要的类，从基础类继承        重写getObjs和getTotalPage函数    '''    def getObjs(self):        find_objs_str = ('{model_name}.objects.all()'.format(model_name = self.model_name))        objs = []        for file in eval(find_objs_str).filter(belongClass__in = self.classType)[self.start_pos:self.end_pos]:            objs.append(file.get_abstract())        return objs    def getTotalPage(self):        # 计算总共的页数          find_objs_count_str = '{model_name}.objects.all()'.format(                                                 model_name = self.model_name)          all_obj_counts = eval(find_objs_count_str).filter(belongClass__in = self.classType).count()        return all_obj_counts

如上，get_abstract()是models.py中自定义的获取表信息的函数，以上两个示例通过重写函数来实现不同的条件需求，灵活许多。