五、分页

5.1 批量插入记录

# 方法一
for i in range(100):
  	Book.objects.create(title='西游记')
# 方法二（推荐）
book_list = []
for i in range(100):
  	obj = Book(title='西游记')
    book_list.append(obj)
Book.objects.bulk_create(book_list)

5.2 批量显示记录

• views.py

  from django.core.paginator import Paginator, EmptyPage
  # 1、获取所有图书记录
  book_list = Book.objects.all()
  # 2、分页处理，每页显示10条
  paginator = Paginator(book_list, 10)
  # 3、当前页码
  current_page_num = int(request.GET.get('page',1))  # 取不到，设置为1
  try:  # 正常页码
      current_page = paginator.page(current_page_num)
  except EmptyPage as e:  # 错误页码，设置为1
    	current_page = paginator.page(1) 
  # 4、显示的页面总个数：(num * 2) + 1
  num = 3
  if paginator.num_pages > (num * 2) + 1:
      if current_page_num - num <= 0:
          page_range = range(1, (num * 2) + 2)
      elif current_page_num + num > paginator.count:
          page_range = range(paginator.count - (num * 2), paginator.count + 1)
      else:
          page_range = range(current_page_num - num, current_page_num + num + 1)
  else:
      page_range = paginator.page_range
  
  print(paginator.count)  # 数据总数
  print(paginator.num_pages)  # 总页数
  print(paginator.page_range)  # 页码列表：range(1,num_pages+1)
  

• index.html

  <!-- 3、遍历当前页所有书籍 -->
  {% for book in current_page %}
  		
  {% endfor %}
  
  <!-- 4、上一页 -->
  {% if current_page.has_previous %}
      <li>
          <a href="?page={{ current_page.previous_page_number }}" aria-label="Next">
              <span aria-hidden="true">&laquo;</span>
          </a>
      </li>
  {% else %}
  		<!-- 没有上一页：disabled、javascript:0 -->
      <li class="disabled">
          <a href="javascript:0" aria-label="Next">
              <span aria-hidden="true">&laquo;</span>
          </a>
      </li>
  {% endif %}
  
  <!-- 4、所有分页 -->
  {% for i in page_range %}
      <!-- 当前页：active -->
      {% if current_page_num == i %}
          <li class="active"><a href="?page={{ i }}">{{ i }}</a></li>
      {% else %}
          <li><a href="?page={{ i }}">{{ i }}</a></li>
      {% endif %}
  {% endfor %}
  
  <!-- 4、下一页 -->
  {% if current_page.has_next %}
      <li>
          <a href="?page={{ current_page.next_page_number }}" aria-label="Next">
              <span aria-hidden="true">&raquo;</span>
          </a>
      </li>
  {% else %}
  		<!-- 没有下一页：disabled、javascript:0 -->
      <li class="disabled">
          <a href="javascript:0" aria-label="Next">
              <span aria-hidden="true">&raquo;</span>
          </a>
      </li>
  {% endif %}
  
  <!-- 是否有上一页：current_page.has_previous -->
  <!-- 上一页：current_page.previous_page_number -->
  <!-- 是否有下一页：current_page.has_next -->
  <!-- 下一页：current_page.next_page_number -->
  

5.3 自定义分页器

• 分页器模块pagination.py

  """
  分页组件
  """
  
  
  class Pagination(object):
      def __init__(self, current_page, all_count, base_url, query_params, per_page=20, pager_page_count=11):
          """
          分页初始化
          :param current_page: 当前页码
          :param all_count: 数据库中总条数
          :param base_url: 基础URL
          :param query_params: QueryDict对象，内部含所有当前URL的原条件
          :param pager_page_count: 页面上最多显示的页码数量
          """
          self.base_url = base_url
          self.query_params = query_params
          self.per_page = per_page
          self.all_count = all_count
          self.pager_page_count = pager_page_count
          pager_count, b = divmod(all_count, per_page)
          if b != 0:
              pager_count += 1
          self.pager_count = pager_count
  
          half_pager_page_count = int(pager_page_count / 2)
          self.half_pager_page_count = half_pager_page_count
  
          # 格式错误的页码或不在范围内的页面，设置为默认值1
          try:
              self.current_page = int(current_page)
              if not (0 < self.current_page <= self.pager_count):
                  raise Exception()
          except Exception as e:
              self.current_page = 1
  
      @property
      def start(self):
          """
          数据获取值起始索引
          :return:
          """
          return (self.current_page - 1) * self.per_page
  
      @property
      def end(self):
          """
          数据获取值结束索引
          :return:
          """
          return self.current_page * self.per_page
  
      def page_html(self):
          """
          生成HTML页码
          :return:
          """
          # 如果数据总页码pager_count<11 pager_page_count
          if self.pager_count < self.pager_page_count:
              pager_start = 1
              pager_end = self.pager_count
          else:
              # 数据页码已经超过11
              # 判断： 如果当前页 <= 5 half_pager_page_count
              if self.current_page <= self.half_pager_page_count:
                  pager_start = 1
                  pager_end = self.pager_page_count
              else:
                  # 如果： 当前页+5 > 总页码
                  if (self.current_page + self.half_pager_page_count) > self.pager_count:
                      pager_end = self.pager_count
                      pager_start = self.pager_count - self.pager_page_count + 1
                  else:
                      pager_start = self.current_page - self.half_pager_page_count
                      pager_end = self.current_page + self.half_pager_page_count
  
          page_list = []
  
          if self.current_page <= 1:
              prev = '<li><a href="javascript: 0;">上一页</a></li>'
          else:
              self.query_params['page'] = self.current_page - 1
              prev = '<li><a href="%s?%s">上一页</a></li>' % (self.base_url, self.query_params.urlencode())
          page_list.append(prev)
  
          for i in range(pager_start, pager_end + 1):
              self.query_params['page'] = i
              if self.current_page == i:
                  tpl = '<li class="active"><a href="%s?%s">%s</a></li>' % (
                      self.base_url, self.query_params.urlencode(), i,)
              else:
                  tpl = '<li><a href="%s?%s">%s</a></li>' % (self.base_url, self.query_params.urlencode(), i,)
              page_list.append(tpl)
  
          if self.current_page >= self.pager_count:
              nex = '<li><a href="javascript: 0;">下一页</a></li>'
          else:
              self.query_params['page'] = self.current_page + 1
              nex = '<li><a href="%s?%s">下一页</a></li>' % (self.base_url, self.query_params.urlencode(),)
          page_list.append(nex)
  
          page_str = "".join(page_list)
          return page_str
  

• 视图函数调用

  from pagination import Pagination
  
  per_page_count = 10
  
  all_count = self.model_class.objects.all().count()
      query_params = request.GET.copy()
      query_params._mutable = True
  
      pager = Pagination(
        current_page=request.GET.get('page'),
        all_count=all_count,
        base_url=request.path_info,
        query_params=query_params,
        per_page=self.per_page_count,
      )
  
      data_list = self.model_class.objects.all()[pager.start:pager.end]
  

• html文件加载

  <nav>
      <ul class="pagination">
        	{{ pager.page_html|safe }}
      </ul>
  </nav>
  

• css样式

  .nav {
      min-width: 980px;
      height: 48px;
      background-color: #2F72AB;
      color: #ffffff;
      line-height: 48px;
      overflow: visible;
      font-size: 12px;
  }
  
  .nav .logo-area {
      width: 220px;
      overflow: hidden;
      height: 48px;
      text-align: center;
      background-color: #1c5a9c;
  }
  
  .nav .logo-area > a {
      color: #ffffff;
      text-decoration: none;
      display: inline-block;
  }
  
  .nav .logo-area .logo {
      height: 37px;
      width: 37px;
      float: left;
      margin: 6px;
      margin-right: 10px;
  }
  
  .nav .left-menu {
      font-size: 13px;
  }
  
  .nav .left-menu .menu-item {
      display: inline-block;
      padding: 0 15px;
      cursor: pointer;
      position: relative;
      color: white;
      text-decoration: none;
  }
  
  .nav .left-menu .menu-item:hover {
      background-color: #337ab7;
  
  }
  
  .nav .left-menu .menu-item .more-info {
      display: none;
      position: absolute;
      top: 48px;
      left: 0;
      border: 1px solid rgba(0, 0, 0, .15);
      -webkit-box-shadow: 0 6px 12px rgba(0, 0, 0, .175);
      box-shadow: 0 6px 12px rgba(0, 0, 0, .175);
      background-color: #fff;
      color: #333;
      z-index: 1003;
  }
  
  .nav .left-menu .menu-item:hover .more-info {
      display: block;
  }
  
  .nav .left-menu .menu-item .more-info .more-item {
      display: block;
      min-width: 120px;
      padding: 0 15px;
      line-height: 35px;
      text-decoration: none;
      color: #000000;
  
  }
  
  .nav .left-menu .menu-item .more-info .more-item:hover {
      background-color: #f1f0f0;
  }
  
  .nav .right-menu .user-menu {
      padding: 0 8px;
      cursor: pointer;
      color: white;
      text-decoration: none;
  }
  
  .nav .right-menu .user-menu:hover {
      background-color: #337ab7;
  
  }
  
  .nav .right-menu .user-info {
      padding: 0 30px 0 10px;
      height: 48px;
      position: relative;
  }
  
  .nav .right-menu .user-info:hover .avatar {
      background-color: #337ab7;
  }
  
  .nav .right-menu .user-info .avatar {
      display: inline-block;
      padding: 0 10px;
      height: 48px;
  }
  
  .nav .right-menu .user-info .avatar img {
      /* margin-top: 2px;*/
  }
  
  .nav .right-menu .user-info .more-info {
      display: none;
      position: absolute;
      top: 48px;
      right: 20px;
      border: 1px solid rgba(0, 0, 0, .15);
      -webkit-box-shadow: 0 6px 12px rgba(0, 0, 0, .175);
      box-shadow: 0 6px 12px rgba(0, 0, 0, .175);
      background-color: #fff;
      color: #333;
      z-index: 1002;
  }
  
  .nav .right-menu .user-info:hover .more-info {
      display: block;
  }
  
  .nav .right-menu .user-info .more-info .more-item {
      display: block;
      min-width: 160px;
      padding: 0 15px;
      line-height: 35px;
      text-decoration: none;
      color: #000000;
  
  }
  
  .nav .right-menu .user-info .more-info .more-item:hover {
      background-color: #f1f0f0;
  }