我们也可以使用基于类的视图编写我们的 API 视图，而不是基于函数的视图。我们将看到这是一个强大的模式，允许我们重用常用功能，并帮助我们保持代码 DRY（Don't repeat yourself）。

我们将首先将根视图重写为基于类的视图。所有这些都是对 apis.py 文件的重构。

from rest_framework import status
from rest_framework.response import Response
from rest_framework.views import APIView

from myApp.models import Book
from myApp.serializers import BookSerializer


class BookList(APIView):

    # 显示所有 book
    def get(self, request, format=None):
        book_list = Book.objects.all()
        book_list_serializer = BookSerializer(book_list, many=True)
        return Response(book_list_serializer.data)

    # 添加一个 book
    def post(self, request, format=None):
        book_serializer = BookSerializer(data=request.data)
        if book_serializer.is_valid():
            book_serializer.save()
            return Response(book_serializer.data, status=status.HTTP_201_CREATED)
        else:
            return Response(book_serializer.errors, status=status.HTTP_400_BAD_REQUEST)

我们还需要重构我们的 urls.py，现在我们使用基于类的视图。

......
from myApp import apis
from rest_framework.urlpatterns import format_suffix_patterns

urlpatterns = [
    ......
    url(r'^api/$', apis.BookList.as_view()),
]

urlpatterns = format_suffix_patterns(urlpatterns)

好了，我们完成了。如果你启动服务，那么它应​​该像之前一样可以运行。

下面我们再来构建单独一个 book 对象的 API，赋予其更多的 HTTP 方法并实现增删查改操作。

from rest_framework import status
from rest_framework.response import Response
from rest_framework.views import APIView

from myApp.models import Book
from myApp.serializers import BookSerializer


class BookDetail(APIView):

    # 获取一个 book 对象
    def get_object(self, pk):
        try:
            return Book.objects.get(pk=pk)
        except Book.DoesNotExist:
            raise Http404

    # 返回某个 book 对象的 API
    # pk 是从 URL 传进来的参数
    def get(self, request, pk, format=None):
        book = self.get_object(pk)
        book_serializer = BookSerializer(book)
        return Response(book_serializer.data)

    # 修改一个 book 对象
    def put(self, request, pk, format=None):
        book = self.get_object(pk)
        book_serializer = BookSerializer(book, data=request.data)
        if book_serializer.is_valid():
            book_serializer.save()
            return Response(book_serializer.data)
        else:
            return Response(book_serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    # 删除一个 book 对象
    def delete(self, request, pk, format=None):
        book = self.get_object(pk)
        book.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

编写 urls.py：

from django.conf.urls import url
from django.contrib import admin

from rest_framework.urlpatterns import format_suffix_patterns

from myApp import apis
from myApp.views import index

urlpatterns = [
    url(r'^admin/', admin.site.urls),

    url(r'^api/$', apis.BookList.as_view()),
    url(r'^api/book/(?P<pk>[0-9]+)/$', apis.BookDetail.as_view()),

    url(r'^index/', index),
]

urlpatterns = format_suffix_patterns(urlpatterns)

现在主键为 1 的 book 对象 API就是：http://127.0.0.1:8000/api/book/1/