Django类视图

一、知识要点概览表

类别	知识点	掌握程度要求
基础视图	View、TemplateView、RedirectView	深入理解
通用显示视图	ListView、DetailView	熟练应用
通用编辑视图	CreateView、UpdateView、DeleteView	熟练应用
Mixin机制	ContextMixin、LoginRequiredMixin	理解原理
视图配置	URL配置、参数传递、模板指定	熟练应用

二、基础视图实现

1. 基本View类

# views.py
from django.views import View
from django.http import HttpResponse
from django.shortcuts import render

class HelloView(View):
    def get(self, request, *args, **kwargs):
        return HttpResponse("Hello, Class-based Views!")
    
    def post(self, request, *args, **kwargs):
        return HttpResponse("POST request received")

class DashboardView(View):
    template_name = 'dashboard.html'
    
    def get(self, request):
        context = {
            'username': request.user.username,
            'page_title': 'Dashboard'
        }
        return render(request, self.template_name, context)

2. TemplateView使用

# views.py
from django.views.generic import TemplateView

class HomePageView(TemplateView):
    template_name = "home.html"
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['page_title'] = '首页'
        context['features'] = [
            '基于类的视图',
            '通用视图',
            'Mixin机制'
        ]
        return context

3. RedirectView示例

# views.py
from django.views.generic import RedirectView

class GitHubRedirectView(RedirectView):
    url = 'https://github.com'
    permanent = False  # 使用302临时重定向
    query_string = True  # 保留查询字符串
    
class OldPostRedirectView(RedirectView):
    permanent = True  # 使用301永久重定向
    
    def get_redirect_url(self, *args, **kwargs):
        post_id = kwargs['post_id']
        return f'/blog/posts/{post_id}/'

三、通用显示视图

1. ListView实现

# models.py
from django.db import models

class Article(models.Model):
    title = models.CharField(max_length=200)
    content = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    is_published = models.BooleanField(default=False)
    
    def __str__(self):
        return self.title

# views.py
from django.views.generic import ListView
from .models import Article

class ArticleListView(ListView):
    model = Article
    template_name = 'articles/article_list.html'
    context_object_name = 'articles'
    paginate_by = 10
    
    def get_queryset(self):
        """只显示已发布的文章"""
        return Article.objects.filter(
            is_published=True
        ).order_by('-created_at')
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['total_articles'] = self.get_queryset().count()
        return context

2. DetailView实现

# views.py
from django.views.generic import DetailView
from django.shortcuts import get_object_or_404

class ArticleDetailView(DetailView):
    model = Article
    template_name = 'articles/article_detail.html'
    context_object_name = 'article'
    
    def get_object(self, queryset=None):
        """自定义获取对象的方法"""
        obj = super().get_object(queryset=queryset)
        # 增加访问次数
        obj.views_count = obj.views_count + 1
        obj.save()
        return obj
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        # 添加相关文章
        context['related_articles'] = Article.objects.filter(
            is_published=True
        ).exclude(
            id=self.object.id
        )[:3]
        return context

四、通用编辑视图

1. CreateView实现

# forms.py
from django import forms
from .models import Article

class ArticleForm(forms.ModelForm):
    class Meta:
        model = Article
        fields = ['title', 'content', 'is_published']
        
    def clean_title(self):
        title = self.cleaned_data['title']
        if len(title) < 5:
            raise forms.ValidationError("标题长度不能少于5个字符")
        return title

# views.py
from django.views.generic.edit import CreateView
from django.urls import reverse_lazy
from .forms import ArticleForm

class ArticleCreateView(CreateView):
    model = Article
    form_class = ArticleForm
    template_name = 'articles/article_form.html'
    success_url = reverse_lazy('article_list')
    
    def form_valid(self, form):
        """表单验证成功时的处理"""
        form.instance.author = self.request.user
        response = super().form_valid(form)
        # 可以在这里添加额外的处理逻辑
        return response
        
    def get_initial(self):
        """设置表单初始值"""
        return {
            'title': '新文章',
            'is_published': False
        }

2. UpdateView实现

# views.py
from django.views.generic.edit import UpdateView
from django.contrib.auth.mixins import LoginRequiredMixin

class ArticleUpdateView(LoginRequiredMixin, UpdateView):
    model = Article
    form_class = ArticleForm
    template_name = 'articles/article_update.html'
    
    def get_success_url(self):
        return reverse_lazy(
            'article_detail',
            kwargs={'pk': self.object.pk}
        )
    
    def get_queryset(self):
        """确保用户只能编辑自己的文章"""
        return Article.objects.filter(author=self.request.user)

3. DeleteView实现

# views.py
from django.views.generic.edit import DeleteView
from django.urls import reverse_lazy
from django.contrib.auth.mixins import UserPassesTestMixin

class ArticleDeleteView(LoginRequiredMixin, UserPassesTestMixin, DeleteView):
    model = Article
    template_name = 'articles/article_confirm_delete.html'
    success_url = reverse_lazy('article_list')
    
    def test_func(self):
        """检查用户是否有权限删除文章"""
        article = self.get_object()
        return self.request.user == article.author
    
    def delete(self, request, *args, **kwargs):
        """自定义删除逻辑"""
        self.object = self.get_object()
        success_url = self.get_success_url()
        # 可以在这里添加其他清理工作
        self.object.delete()
        return HttpResponseRedirect(success_url)

五、类视图的URL配置

# urls.py
from django.urls import path
from . import views

app_name = 'articles'

urlpatterns = [
    path('', views.ArticleListView.as_view(), name='article_list'),
    path('<int:pk>/', views.ArticleDetailView.as_view(), name='article_detail'),
    path('create/', views.ArticleCreateView.as_view(), name='article_create'),
    path('<int:pk>/update/', views.ArticleUpdateView.as_view(), name='article_update'),
    path('<int:pk>/delete/', views.ArticleDeleteView.as_view(), name='article_delete'),
]

六、类视图执行流程图

七、Mixin的使用

1. 自定义Mixin

class TitleMixin:
    title = ''
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['title'] = self.title
        return context

class AuthorRequiredMixin:
    """确保用户是作者的Mixin"""
    def dispatch(self, request, *args, **kwargs):
        obj = self.get_object()
        if obj.author != request.user:
            raise PermissionDenied
        return super().dispatch(request, *args, **kwargs)

class PageTitleMixin:
    page_title = ''
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['page_title'] = self.page_title
        return context

# 使用Mixin
class ArticleDetailView(TitleMixin, PageTitleMixin, DetailView):
    model = Article
    template_name = 'articles/article_detail.html'
    title = '文章详情'
    page_title = '查看文章'

2. 常用Mixin组合

from django.contrib.auth.mixins import (
    LoginRequiredMixin,
    PermissionRequiredMixin
)

class ArticleAdminView(
    LoginRequiredMixin,
    PermissionRequiredMixin,
    ListView
):
    model = Article
    template_name = 'articles/admin_list.html'
    permission_required = 'articles.view_article'
    
    def get_queryset(self):
        return Article.objects.all().order_by('-created_at')

class StaffRequiredMixin(UserPassesTestMixin):
    def test_func(self):
        return self.request.user.is_staff

class ArticleStaffView(StaffRequiredMixin, ListView):
    model = Article
    template_name = 'articles/staff_list.html'

八、模板示例

<!-- templates/articles/article_list.html -->
{% extends 'base.html' %}

{% block content %}
<div class="container">
    <h1>{{ page_title }}</h1>
    
    <div class="article-list">
        {% for article in articles %}
        <div class="article-item">
            <h2>{{ article.title }}</h2>
            <p>{{ article.content|truncatewords:30 }}</p>
            <div class="article-meta">
                <span>作者: {{ article.author }}</span>
                <span>发布时间: {{ article.created_at|date:"Y-m-d" }}</span>
            </div>
            <div class="article-actions">
                <a href="{% url 'articles:article_detail' article.pk %}"
                   class="btn btn-primary">
                    查看详情
                </a>
                {% if user == article.author %}
                <a href="{% url 'articles:article_update' article.pk %}"
                   class="btn btn-secondary">
                    编辑
                </a>
                <a href="{% url 'articles:article_delete' article.pk %}"
                   class="btn btn-danger">
                    删除
                </a>
                {% endif %}
            </div>
        </div>
        {% empty %}
        <p>暂无文章</p>
        {% endfor %}
    </div>
    
    {% if is_paginated %}
    <nav aria-label="Page navigation">
        <ul class="pagination">
            {% if page_obj.has_previous %}
            <li class="page-item">
                <a class="page-link" href="?page={{ page_obj.previous_page_number }}">
                    上一页
                </a>
            </li>
            {% endif %}
            
            {% for num in page_obj.paginator.page_range %}
            <li class="page-item {% if page_obj.number == num %}active{% endif %}">
                <a class="page-link" href="?page={{ num }}">{{ num }}</a>
            </li>
            {% endfor %}
            
            {% if page_obj.has_next %}
            <li class="page-item">
                <a class="page-link" href="?page={{ page_obj.next_page_number }}">
                    下一页
                </a>
            </li>
            {% endif %}
        </ul>
    </nav>
    {% endif %}
</div>
{% endblock %}

这就是关于Django类视图的详细内容。通过学习这些内容，将能够理解和使用Django的类视图系统，实现更加优雅和可维护的视图逻辑。如果有任何问题，欢迎随时提出！

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