16 博客分类统计

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本教程来源于B站杨仕航Django2.0开发视频教程，如需转载，必须注明来源！

1.按博客类型分类统计博客数量

• 方法1：给BlogType模型手动增加一个blog_count字段信息，便于统计属于某种类型下的博客数量。打开blog文件目录下的views.py文件，修改blog_list_common_data()增加获取某一特定类别的博客数量功能的代码段，如下所示：

  def blog_list_common_data(request, blogs_all_list):
      paginator = Paginator(
          blogs_all_list, settings.EACH_PAGE_BLOGS_NUMBER)
      page_num = request.GET.get('page', 1)  # 获取url的页码参数(GET请求)
      page_of_blogs = paginator.get_page(page_num)
      current_page_num = page_of_blogs.number  # 获取当前页码
      # 获取当前页码前后各两页的页码范围
      page_range = list(range(max(current_page_num - 2, 1), current_page_num)) + \
          list(range(current_page_num, min(
              current_page_num + 2, paginator.num_pages) + 1))
      # 加上省略页码标记
      if page_range[0] - 1 >= 2:
          page_range.insert(0, '...')
      if paginator.num_pages - page_range[-1] >= 2:
          page_range.append('...')
  
      # 加上首页和尾页
      if page_range[0] != 1:
          page_range.insert(0, 1)
      if page_range[-1] != paginator.num_pages:
          page_range.append(paginator.num_pages)
  
      # 方法1：获取某一特定类别的博客数量
      blog_types = BlogType.objects.all()
      blog_types_list = []
      for blog_type in blog_types:
          blog_type.blog_count = Blog.objects.filter(blog_type=blog_type).count()
          blog_types_list.append(blog_type)
  
      context = {}
      context['blogs'] = page_of_blogs.object_list
      context['page_of_blogs'] = page_of_blogs
      context['page_range'] = page_range
      context['blog_types'] = blog_types_list
      context['blog_dates'] = Blog.objects.dates(
          "created_time", "month", order="DESC")
      return context
  

• 接着，修改templates文件夹下的blog_list.html模板文件，增加显示属于某一特定类别的博客数量代码。如下所示：

  <div class="panel panel-default">
      <div class="panel-heading">
          博客分类
      </div>
      <div class="panel-body">
          <ul class="blog-types">
              {% for blog_type in blog_types %}
                  <li>
                      <a href="{% url 'blogs_with_type' blog_type.pk %}">{{ blog_type.type_name }} ({{ blog_type.blog_count }})
                      </a>
                  </li>
              {% empty %}
                  <li>暂无分类</li>
              {% endfor %}
          </ul>
      </div>
  </div>
  

• 方法2：annotate注释：使用annotate扩展查询字段。

  from django.shortcuts import render_to_response, get_object_or_404
  from django.core.paginator import Paginator
  from django.conf import settings
  from django.db.models import Count
  from .models import Blog, BlogType
  # Create your views here.
  
  def blog_list_common_data(request, blogs_all_list):
      paginator = Paginator(
          blogs_all_list, settings.EACH_PAGE_BLOGS_NUMBER)
      page_num = request.GET.get('page', 1)  # 获取url的页码参数(GET请求)
      page_of_blogs = paginator.get_page(page_num)
      current_page_num = page_of_blogs.number  # 获取当前页码
      # 获取当前页码前后各两页的页码范围
      page_range = list(range(max(current_page_num - 2, 1), current_page_num)) + \
          list(range(current_page_num, min(
              current_page_num + 2, paginator.num_pages) + 1))
      # 加上省略页码标记
      if page_range[0] - 1 >= 2:
          page_range.insert(0, '...')
      if paginator.num_pages - page_range[-1] >= 2:
          page_range.append('...')
  
      # 加上首页和尾页
      if page_range[0] != 1:
          page_range.insert(0, 1)
      if page_range[-1] != paginator.num_pages:
          page_range.append(paginator.num_pages)
  
      # 方法2：获取某一特定类别的博客数量
      # BlogType.objects.annotate(blog_count=Count("blog"))
      context = {}
      context['blogs'] = page_of_blogs.object_list
      context['page_of_blogs'] = page_of_blogs
      context['page_range'] = page_range
      context['blog_types'] = BlogType.objects.annotate(blog_count=Count("blog"))
      context['blog_dates'] = Blog.objects.dates(
          "created_time", "month", order="DESC")
      return context
  

2.按日期归档统计博客数量

• 打开blog文件目录下的views.py文件，修改blog_list_common_data()增加获取按日期归档统计博客数量功能的代码段，如下所示：

  def blog_list_common_data(request, blogs_all_list):
      paginator = Paginator(
          blogs_all_list, settings.EACH_PAGE_BLOGS_NUMBER)
      page_num = request.GET.get('page', 1)  # 获取url的页码参数(GET请求)
      page_of_blogs = paginator.get_page(page_num)
      current_page_num = page_of_blogs.number  # 获取当前页码
      # 获取当前页码前后各两页的页码范围
      page_range = list(range(max(current_page_num - 2, 1), current_page_num)) + \
          list(range(current_page_num, min(
              current_page_num + 2, paginator.num_pages) + 1))
      # 加上省略页码标记
      if page_range[0] - 1 >= 2:
          page_range.insert(0, '...')
      if paginator.num_pages - page_range[-1] >= 2:
          page_range.append('...')
  
      # 加上首页和尾页
      if page_range[0] != 1:
          page_range.insert(0, 1)
      if page_range[-1] != paginator.num_pages:
          page_range.append(paginator.num_pages)
  
      # 方法1：获取某一特定类别的博客数量
      '''
      blog_types = BlogType.objects.all()
      blog_types_list = []
      for blog_type in blog_types:
          blog_type.blog_count = Blog.objects.filter(blog_type=blog_type).count()
          blog_types_list.append(blog_type)
      '''
      # 方法2：获取某一特定类别的博客数量
      # BlogType.objects.annotate(blog_count=Count("blog"))
  
      # 方法：获取按日期归档对应的博客数量
      # blog_dates是一个datetime数据类型，即<QuerySet [datetime.date(2020, 5, 1)]>
      blog_dates = Blog.objects.dates("created_time", "month", order="DESC")
      blog_dates_dict = {}
      for blog_date in blog_dates:
          blog_count = Blog.objects.filter(created_time__year=blog_date.year,
                                           created_time__month=blog_date.month).count()
          blog_dates_dict[blog_date] = blog_count
  
      context = {}
      context['blogs'] = page_of_blogs.object_list
      context['page_of_blogs'] = page_of_blogs
      context['page_range'] = page_range
      context['blog_types'] = BlogType.objects.annotate(blog_count=Count("blog"))
      context['blog_dates'] = blog_dates_dict
      return context
  

• 接着，修改templates文件夹下的blog_list.html模板文件，增加显示按日期归档显示博客数量的代码。如下所示：

  <div class="panel panel-default">
      <div class="panel-heading">
          日期归档
      </div>
      <div class="panel-body">
          <ul>
              {% for blog_date, blog_count in blog_dates.items %}
                  <li>
                      <a href="{% url 'blogs_with_date' blog_date.year blog_date.month %}">
                          {{ blog_date|date:"Y年m月" }} ({{ blog_count }})
                      </a>
                  </li>
              {% endfor %}
          </ul>
      </div>
  </div>
  

3.效果展示

效果展示.png