16 博客分类统计

技术交流QQ群:1027579432，欢迎你的加入！

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