django类视图介绍与类视图装饰器

django框架是MTV框架

views.py中def定义的视图是基于函数的视图，class定义的视图是基于类的视图。  --- 分为普通类视图，通用类视图

- 特定的Http方法，get post单独的方法。

- 继承，多重继承 代码分解成可以复用的组件。

1.类视图介绍

普通类视图，目的在于：特定的Http方法，get post单独的方法。

重写views.py中的index。改写成类IndexView。

from django.views import View   #导入类视图

class IndexView(View):
    def get(self,request):
        num = request.COOKIES.get('num',None)
        if num:
            num = str(int(num)+1)
        else:
            num = 1
        response=render(request,'teacher/index.html',context={
            'num':num
        })
        response.set_cookie('num',num,max_age=20) #max_age保存多少秒，整数,expiry设置过期时间
        return response
    def post(self,request):   还可以重写post等。
        pass

urls.py路由中做如下修改：

path('index/', views.IndexView.as_view(),name='index'),

实例二，使用普通类视图，重写编辑学生详情的new_edit方法

class EditStudentView(View):
    student_form_class = StudentForm   #绑定Form表单绑定
    student_detail_form_class = StudentDetailForm
    template_name = 'teacher/student_edit_form.html'
    section = '学生信息修改'

    def get(self,request,pk):
        student = Student.objects.get(pk=pk)
        # grades = Grade.objects.all()
        form = self.student_form_class(instance=student)

        try:
            detail_form = self.student_detail_form_class(instance=student.studentdetail)
        except:
            # 说明学生对象还没有学生详情
            student_detail = StudentDetail()
            student_detail.student = student
            student_detail.save()
            detail_form = self.student_detail_form_class(instance=student_detail)
        return  render(request,'teacher/student_edit_form.html',context={
            'section':self.section,
            'student':student,
            'form':form,
            'detail_form':detail_form
        })

    def post(self,request,pk):
        student = Student.objects.get(pk=pk)

        form = self.student_form_class(request.POST, instance=student)
        detail_form = self.student_detail_form_class(request.POST, instance=student.studentdetail)

        if form.is_valid() and detail_form.is_valid():
            form.save()
            detail_form.save()
            return redirect(reverse('teacher:students'))


        return render(request, 'teacher/student_edit_form.html', context={
            'section': self.section,
            'student': student,
            'form': form,
            'detail_form': detail_form
    })

修改路由urls.py

path('newedit/<int:pk>/',views.EditStudentView.as_view(),name='new_edit'),

通用类视图：ListView

重写students view视图

from django.views.generic import ListView #通用视图

class StudentListView(ListView):
    template_name = 'teacher/students.html'
    model = Student
    context_object_name = 'students'
    paginate_by = 3
    section = '学生列表'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['section']=self.section
        context['search'] = self.request.GET.get('search','').strip()
        context['per_page'] = self.paginate_by
        context['page'] = int(self.request.GET.get('page',1))
        context['students'] = context['page_obj']
        return context

    def get_queryset(self):#改变渲染到模板前面的对象列表
        # 获取查询参数
        search = self.request.GET.get('search', '').strip()
        # 每页显示多少数据
        per_page = self.request.GET.get('per_page', 10)
        self.paginate_by = int(per_page)
        if search:
            if search.isdigit():
                sts = self.model.objects.filter(Q(qq=search) | Q(phone=search), is_deleted=False).order_by('-e_time')
                # 是qq或者电话
            else:
                sts = self.model.objects.filter(name__contains=search, is_deleted=False).order_by('-e_time')
        else:
            sts = self.model.objects.filter(is_deleted=False).order_by('-e_time')
        return sts

urls.py修改

path('newstudents/',views.StudentListView.as_view(),name='newstudents'),

通用类视图：DetailView

重写学生详情

views.py中添加

from django.views.generic import ListView,DetailView

class StudentDetailView(DetailView):
    template_name = 'teacher/student_detail.html'
    model = Student

urls.py中添加

    path('studentdetail/<int:pk>/',views.StudentDetailView.as_view())

渲染页面student_detail.html

<body>
    {{ object }}
</body>
</html>

3. 类视图装饰器(2种方法）

在urls中装饰 ,必须登录才能查看 (适用于在主目录下对所有路径添加，所有都需要验证的情况)

from django.contrib.auth.decorators import login_required

 path('newstudents/',login_required(views.StudentListView.as_view()),name='newstudents'),

第二种方法：

装饰类

1.如果没有显示指定get,post方法，直接装饰分发的装饰器

from django.utils.decorators import method_decorator #方法装饰器

class StudentListView(ListView):
    template_name = 'teacher/students.html'
    model = Student
    # context_object_name = 'students'
    paginate_by = 3
    section = '学生列表'

    @method_decorator(login_required)
    def dispatch(self, request, *args, **kwargs):
        return super().dispatch(request,*args, **kwargs)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['section']=self.section
        context['search'] = self.request.GET.get('search','').strip()
        context['per_page'] = self.paginate_by
        context['page'] = int(self.request.GET.get('page',1))
        context['students'] = context['page_obj']
        return context

    def get_queryset(self):#改变渲染到模板前面的对象列表
        # 获取查询参数
        search = self.request.GET.get('search', '').strip()
        # 每页显示多少数据
        per_page = self.request.GET.get('per_page', 10)
        self.paginate_by = int(per_page)
        if search:
            if search.isdigit():
                sts = self.model.objects.filter(Q(qq=search) | Q(phone=search), is_deleted=False).order_by('-e_time')
                # 是qq或者电话
            else:
                sts = self.model.objects.filter(name__contains=search, is_deleted=False).order_by('-e_time')
        else:
            sts = self.model.objects.filter(is_deleted=False).order_by('-e_time')
        return sts

2.或者直接装饰，get,post

class IndexView(View):
    @method_decorator(login_required)
    def get(self,request):
        num = request.COOKIES.get('num',None)
        if num:
            num = str(int(num)+1)
        else:
            num = 1
        response=render(request,'teacher/index.html',context={
            'num':num
        })
        response.set_cookie('num',num,max_age=20) #max_age保存多少秒，整数,expiry设置过期时间
        return response

3.装饰类 ，两个参数，第一个是使用的login验证方法，第二个是dispatch。分发

@method_decorator(login_required,name='dispatch')
class StudentListView(ListView):
    template_name = 'teacher/students.html'
    model = Student
    # context_object_name = 'students'
    paginate_by = 3
    section = '学生列表'