DRF-->1 序列化组件的使用和接口设计---get

                    - 导入模块：from rest_framework import serializers
                    - 建立一个序列化类
                        class BookSerializer(serializers.Serializer):
                            字段可以自定义
                            
                    - 获取客户端请求数据
                    - 开始序列化
                        serialized_data = BookSerializer(origin_data, many=True)
                    - 写入数据库
                    - 获取序列化后的数据，返回给客户端
                        return Response(serialized_data.data)

　　　　　　　　　 GET       127.0.0.1:8000/books/     # 获取所有数据，返回值: [{}, {}]
                GET       127.0.0.1:8000/books/{id} # 获取一条数据，返回值：{}
                POST      127.0.0.1:8000/books/     # 新增一条数据，返回值：{}
                PUT       127.0.0.1:8000/books/{id} # 修改数据，返回值：{}
                DELETE    127.0.0.1:8000/books/{id} # 删除数据，返回空

models.py
#表
class Author(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    age = models.IntegerField()

    def __str__(self):
        return self.name


class Publish(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=32)
    email = models.EmailField()

    def __str__(self):
        return self.name


class Book(models.Model):
    nid = models.AutoField(primary_key=True)
    title = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    # 外键字段
    publish = models.ForeignKey(to="Publish", related_name="book", related_query_name="book_query", on_delete=models.CASCADE)
    # 多对多字段
    authors = models.ManyToManyField(to="Author")

python manage.py makemigrations
python manage.py migrate

urls.py
from django.contrib import admin
from django.urls import path
from app1 import views

urlpatterns = [
    path(‘admin/‘, admin.site.urls),
    path(‘books/‘,views.BookView.as_view()),
]




views.py
from rest_framwork.views import APIView
from rest_framwork import serializers
from rest_fromwork.response import Response

class BookView(APIView):
    def get(self,request):
        book_list = Book.objects.all()
        # print(book_list)
#进行数据的序列化
        serializer_book_list = BookSerializer(book_list,many=True)
#返回的时候必须带着data，因为所有的数据都在data里
        return Response(serializer_book_list.data)

    def post(self,request):
        pass

urls.py
calss BookSerializer(serializers,Serializer):
    title = serializers.CharField(max_length=32)
    price = serializers.DecimalField(max_digits=5,decimal_places=2)
    publish = serializers.CharField(max_length=32)
    author= serializers.CharField(max_length=32)

url.py

class BookSerializer(serializers.Serializer):
    title = serializers.CharField(max_length=32)
    price = serializers.DecimalField(max_digits=5,decimal_places=2)
    publish = serializers.CharField(max_length=32)
    #这里必须是用SerializerMethodField()！！！
    authors_list = serializers.SerializerMethodField()
#方法里有一个get_方法，注意！！！authors_list必须和上边的序列化一致否则报错找不到对应的方法！
    def get_authors_list(self,book_obj):
        author_list = list()
        for author in book_obj.authors.all():
            author_list.append(author.name)
        return author_list