序列化器Serializer

作用：

1. 序列化，序列化器会把模型对象转换成字典，经过request以后变成json字符串
2. 反序列化，把客户端发送过来的数据，经过request以后变成字典(request.data)，序列化器(类)可以把字典转成模型
3. 反序列化，完成数据校验功能

本质就是写一个类，继承基类。

可以完成序列化，反序列化和数据校验。

读取数据为序列化，新增为反序列化。

通过serizlizer实现五个接口，此为第一步。

查询所有接口，新增数据接口

serizlizer.py

"""
与表没有关系，需要自己建关系
from rest_framework.serializers import Serializer
"""
from rest_framework import serializers# 需要序列化和反序列化Book表，可称呼为序列化类
class BoookSerializers(serializers.Serializer):# 写字段(需要序列化，反序列化的字段)name = serializers.CharField()price = serializers.IntegerField()publish = serializers.CharField()# 新增需要重写createdef create(self, validated_data):# {'name': '新增2', 'price': 10, 'publish': '测试出版社'}# print(validated_data)book = Books.objects.create(**validated_data)# Books object (7)# print(book)return book

views.py，发序列化新增，序列化读取。

"""
drf使用方式：CBV，继承的类，是drf提供的类，APIView
使用drf 多了一个Response类
"""
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.request import Request
from .serizlizer import BoookSerializers
from .models import Booksclass BookAPIView(APIView):# 查询所有的接口def get(self, request, *args, **kwargs):# 从数据库中把所有的数据取出,取出Books所有的queryset对象book_list = Books.objects.all()# <QuerySet [<Books: Books object (1)>, <Books: Books object (3)>]>print(book_list)"""类实例化得到对象(ser),并转为字典，此处为序列化过程，把queryset转成字典BookSerializers(需要序列化的queryset对象,data=None可以不传,如果序列化多条数据需要加many=True)"""ser = BoookSerializers(instance=book_list, many=True)"""字典[OrderedDict([('name', '葫芦娃'), ('price', 10), ('publish', '测试出版社')]), OrderedDict([('name', '互撸娃'), ('price', 10000), ('publish', '娃哈哈出版社')])]"""print(ser.data)# <class 'rest_framework.utils.serializer_helpers.ReturnList'>print(type(ser.data))# ser.data 序列化转成字典return Response(ser.data)# 新增def post(self,request,*args, **kwargs):# <rest_framework.request.Request: POST '/books/'>print(request)# {'name': '新增8', 'price': 10, 'publish': '测试出版社'}print(request.data)ser = BookSerializers(data=request.data)if ser.is_valid():ser.save()return Response(ser.data)

url.py

from django.contrib import admin
from django.urls import path
from app01 import views
# from rest_framework.routers import SimpleRouterurlpatterns = [path('admin/', admin.site.urls),# drf 继承APIView 的路由，向books地址发送请求，将所有图书返回path('books/', views.BookAPIView.as_view())]

查询单个接口，删除单个接口，修改

Serializers.py

from rest_framework import serializers# 需要序列化和反序列化Book表
class BookSerializers(serializers.Serializer):# 写字段(需要序列化，反序列化的字段)name = serializers.CharField()price = serializers.IntegerField()publish = serializers.CharField()# 如果要更新，一定要重写updata方法def update(self, instance, validated_data):# Books object (1)print(instance)instance.name = validated_data.get('name')# jajajaj 修改的数据print(instance.name)instance.price = validated_data.get('price')instance.publish = validated_data.get('publish')# 保存instance.save()# 返回return instance

url.py

from django.contrib import admin
from django.urls import path
from app01 import views
# from rest_framework.routers import SimpleRouterurlpatterns = [path('admin/', admin.site.urls),# drf 继承APIView 的路由，向books地址发送请求，将所有图书返回path('books/', views.BookAPIView.as_view()),# <int:pk> 转换器,int为定义类型,数据类型可自定义。path('books/<int:pk>', views.BookDetilAPIView.as_view()),
]

views.py

class BookDetilAPIView(APIView):# 查询单个接口def get(self,request,pk):book = Books.objects.filter(pk=pk).first()# Books object (1)# print(book)# <class 'app01.models.Books'># print(type(book))"""此处为序列化过程，把queryset转成字典many=True 需要改为False，此时为查询单条数据，不写，many默认为False，"""ser = BookSerializers(instance=book)return Response(ser.data)# 删除单个接口def delete(self,request,pk):Books.objects.filter(pk=pk).delete()return Response()# 修改单条数据def put(self,request,pk):# <rest_framework.request.Request: PUT '/books/1'># print(request)book = Books.objects.filter(pk=pk).first()# {'name': '哈哈哈', 'price': 10, 'publish': '测试出版社'},内部自动返序列化# print(request.data)ser = BookSerializers(instance=book,data=request.data)# 校验数据if ser.is_valid():ser.save()return Response(ser.data)