继承APIView

from rest_framework.views import APIView


class PageView(APIView):

    def get(self,request):
        #获取所有用户
        users = User.objects.all()
        #创建分页对象
        pg = PageNumberPagination()
        #获取分页数据
        page_users = pg.paginate_queryset(queryset=users,request=request)
        #序列化
        ser = PageUserSerializer(instance=page_users,many=True)
        #使用restframework提供的Response
        return Response(ser.data)

继承GenericAPIView

GenericAPIView继承自APIView
和上面继承APIView流程上没有区别，只是将各个功能封装好

from rest_framework.generics import GenericAPIView


class Page1View(GenericAPIView):
    queryset = User.objects.all()
    serializer_class =  PageUserSerializer
    pagination_class = PageNumberPagination

    def get(self,request):
        #获取所有用户
        users = self.get_queryset()
        # 获取分页数据
        page_users = self.paginate_queryset(users)
        #序列化
        ser = self.get_serializer(instance=page_users,many=True)
        #使用restframework提供的Response
        return Response(ser.data)

继承GenericViewSet

GenericViewSet继承关系：

class GenericViewSet(ViewSetMixin, generics.GenericAPIView)

ViewSetMixin中也重新了as_view()，优先执行，并且改变了路由的写法
路由定义：path('page2_view', Page2View.as_view({'get': 'list'})),
将get请求指定list()处理，其他没有变动，代码如下：

from rest_framework.viewsets import GenericViewSet


class Page2View(GenericViewSet):
    queryset = User.objects.all()
    serializer_class =  PageUserSerializer
    pagination_class = PageNumberPagination

    def list(self,request):
        #获取所有用户
        users = self.get_queryset()
        # 获取分页数据
        page_users = self.paginate_queryset(users)
        #序列化
        ser = self.get_serializer(instance=page_users,many=True)
        #使用restframework提供的Response
        return Response(ser.data)

继承ListModelMixin

查看ListModelMixin源码，里面定义的list()源码其实跟上面自己写的一样

class ListModelMixin:
    """
    List a queryset.
    """
    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

        serializer = self.get_serializer(queryset, many=True)
        return Response(serializer.data)

路由定义：path('page3_view', Page3View.as_view({'get': 'list'})),
继承自ListModelMixin和GenericViewSet，功能更强大，业务代码更精简：

from rest_framework.mixins import ListModelMixin


class Page3View(ListModelMixin,GenericViewSet):
    queryset = User.objects.all()
    serializer_class =  PageUserSerializer
    pagination_class = PageNumberPagination

ListModelMixin帮我们实现了get请求对应的list()方法，可以获取所有记录，如果要实现增加、删除、修改、查找单条记录怎么写？

继承ModelViewSet

ModelViewSet继承关系如下，可以实现增删改查

class ModelViewSet(mixins.CreateModelMixin,
                   mixins.RetrieveModelMixin,
                   mixins.UpdateModelMixin,
                   mixins.DestroyModelMixin,
                   mixins.ListModelMixin,
                   GenericViewSet):

业务代码实现如下，代码进一步精简，并且具备增删改查功能

from rest_framework.viewsets import ModelViewSet


class Page4View(ModelViewSet):
    queryset = User.objects.all()
    serializer_class =  PageUserSerializer
    pagination_class = PageNumberPagination

路由定义(一个url对应了两个路由)：

    path('page4_view', Page4View.as_view({'get': 'list','post':'create'})),
    re_path('page4_view/(?P<pk>\d+)/', Page4View.as_view({'get': 'retrieve','delete':'destroy','put':'update','patch':'partial_update'})),#根据id 查找单个对象/删除/更新单个对象全部内容/局部更新

支持比如?form=json和.json方式请求

    path('page4_view', Page4View.as_view({'get': 'list','post':'create'})),#http://localhost:8000/page4_view?format=json
    re_path('page4_view\.(?P<format>\w+)', Page4View.as_view({'get': 'list','post':'create'})),#http://localhost:8000/page4_view.json
    re_path('page4_view/(?P<pk>\d+)/', Page4View.as_view({'get': 'retrieve','delete':'destroy','put':'update','patch':'partial_update'})),#http://localhost:8000/page4_view/1/?format=json
    re_path('page4_view/(?P<pk>\d+)\.(?P<format>\w+)/', Page4View.as_view({'get': 'retrieve','delete':'destroy','put':'update','patch':'partial_update'})),#http://localhost:8181/page4_view/1.json

restframework提供了更简单的方式，等同上面的4个url

from rest_framework import routers

router = routers.DefaultRouter()
router.register(r'xxx',Page4View)#http://localhost:8000/xxx?format=json，http://localhost:8000/xxx.json，http://localhost:8000/xxx/1/?format=json，http://localhost:8181/xxx/1.json

urlpatterns = [
   ... 
   path('', include(router.urls)),
]

总结

基本增删改查 使用ModelViewSet
复杂逻辑 使用APIView或者GenericViewSet(路由中可以自定义请求方式对应的处理方法，示例中通过两条路由区分多条查询和单条查询)

视图继承关系