Django序列化组件Serializers详解

from django.db import models# Create your models here.class Book(models.Model):
id = models.IntegerField(primary_key=True)
title = models.CharField(max_length=255)
desc = models.CharField(max_length=255)
is_deleted = models.IntegerField(choices=[(1, "删除"), (0, "未删除")])
author = models.CharField(max_length=255)

from rest_framework.serializers import Serializer
from rest_framework import serializersclass BookSerializer(Serializer):
id = serializers.IntegerField()
title = serializers.CharField()
desc = serializers.CharField()
is_deleted = serializers.ChoiceField(choices=[(1, "删除"), (0, "未删除")], source="get_is_deleted_display")
author = serializers.CharField()

from app01.models import Book
from app01.serializer import BookSerializer
from django.http import HttpResponse, JsonResponse# Create your views here.def get_books(request):
books = Book.objects.all()
se = BookSerializer(books, many=True)
return JsonResponse(se.data, safe=False)

[{"id": 1, "title": "活着", "desc": "讲述一代人的人生", "is_deleted": "未删除", "author": "余华"}]

serializer = CommentSerializer(data={'email': 'foobar', 'content': 'baz'})
serializer.is_valid()
# False
serializer.errors
# {'email': ['Enter a valid e-mail address.'], 'created': ['This field is required.']}

def multiple_of_ten(value):
if value % 10 != 0:
raise serializers.ValidationError('Not a multiple of ten')class GameRecord(serializers.Serializer):
score = IntegerField(validators=[multiple_of_ten])

from rest_framework import serializersclass BlogPostSerializer(serializers.Serializer):
title = serializers.CharField(max_length=100)
content = serializers.CharField() def validate_title(self, value):
"""
Check that the blog post is about Django.
"""
if 'django' not in value.lower():
raise serializers.ValidationError("Blog post is not about Django")
return value

from rest_framework import serializersclass EventSerializer(serializers.Serializer):
description = serializers.CharField(max_length=100)
start = serializers.DateTimeField()
finish = serializers.DateTimeField() def validate(self, data):
"""
Check that start is before finish.
"""
if data['start'] > data['finish']:
raise serializers.ValidationError("finish must occur after start")
return data

class CommentSerializer(serializers.Serializer):
email = serializers.EmailField()
content = serializers.CharField(max_length=200)
created = serializers.DateTimeField()

def create(self, validated_data):
return Comment.objects.create(**validated_data) def update(self, instance, validated_data):
instance.email = validated_data.get('email', instance.email)
instance.content = validated_data.get('content', instance.content)
instance.created = validated_data.get('created', instance.created)
instance.save()
return instance

# .save() will create a new instance.
serializer = CommentSerializer(data=data)

serializer.save()

# .save() will update the existing `comment` instance.
serializer = CommentSerializer(comment, data=data)serializer.save()

serializer.save(owner=request.user)

class AccountSerializer(serializers.ModelSerializer):
class Meta:
model = Account
fields = ['id', 'account_name', 'users', 'created']

from res_framework import serializers#这个类用于被实例化，多对多字段这么写
class AuthorSerializer(serializers.Serializer):
id = serializers.Charfield()
name = serializers.Charfield()
age = serializers.Charfield()#传给views.py的主类
class BookSerializer(serializers.Serializer):
name = serializers.Charfield()
#source 可以指定字段 , id是要序列化的表名。
id = serializers.CharField(source='nid')
#，source后字段用.的方式可以跨表查询。
publish = serializer.CharField(source='publish.email')
'''
如果在models.py的book类中定义一个test方法。
def test(self):
return str(self.price)+self.name
'''
# 返回的结果就会有xx字段，souce不但可以指定表模型字段，还可以指定模型表方法，并且赋值给xx变量
xx = serializers.Charfield(source='test') #外键的实现方法：
#一对多字段
#如果要通过外键字段返回出版社的所有信息，包括id,name,email...
#obj是当前循环序列化到的数据对象
publish = serializers.SerializerMethodField()
def get_publish(self,obj):
return {’id‘:obj.publish.pk,'name':obj.publish.name} #多对多字段
#所有作者的详情，也展示出来
authors = serializers.SerializermethodFiled()
def get_authors(self,obj):
author_list = obj.authors.all()
author_ser = AuthorSerializer(author_list,many=True)
return author_ser.data

from rest_framework.views import APIView
from rest_framework.response import Response
from app01 import modelsclass BookView(APIview):
def get(self,request,*args,**kwargs)：
#获取所有图书数据
response = {'status':100,'msg':'获取成功'}
book_list = models.Book.objects.all()
#实例化BookSerializer类，把要序列化的数据book_list传入
#如果要序列化querySet对象，一定要加many = True
book_ser = BookSerializer(book_list,many=True)
#把序列化后的数据book_ser.data 拿出来放到response字典中返回给客户端
response['data'] = book_ser.data
return Response(response)

from app01 import models
class PublishSerializer(serializers.ModelSerializer):
class Meta: #固定写法
# 指定要序列化Book表
model = models.Book
#指定要序列化的字段
fields = ['nid','name']
#序列化所有字段
fileds ='__all__‘
#要排除的字段（不能与fileds连用）
# exclude = ['name','price']
#深度判定
depth = 1
#如果要不按照父类的来，想要自己定义显示的字段的话,自己定义一个，覆盖掉父类的字段属性。
publish = serializers.SerializerMethodField() #一对多字段
def get_publish(self,obj):
return {’id‘:obj.publish.pk,'name':obj.publish.name}

def to_representation(self, instance):
"""Convert `username` to lowercase."""
ret = super().to_representation(instance)
ret['username'] = ret['username'].lower()
return ret

def to_internal_value(self, value):
if value == None:
return 0
return value