閱讀目錄

序列化：將Python對象準換成json格式的字符串，反之即為反序列化

DRF的序列化使用過程：

使用drf的序列化組件
-1 新建一個序列化類繼承Serializer
-2 在類中寫要序列化的字段

-在視圖中使用序列化的類
-1 實例化序列化的類產生對象,在產生對象的時候，傳入需要序列化的對象（queryset）
-2 對象.data
-3 return Response(對象.data)

使用示例：

新建Django項目：settings.py文件注冊rest_framework，使用MySQL數據庫創建數據

-------------------------------------------------------------------- 注：如果你對python感興趣，我這有個學習Python基地，里面有很多學習資料，感興趣的+Q群：895817687 --------------------------------------------------------------------# settings.py DATABASES = {'default': {'ENGINE': 'django.db.backends.mysql','NAME': 'drf_ser01','HOST': '127.0.0.1','PORT': 3306,'USER': 'root','PASSWORD': '123'} }# __init__.py import pymysql pymysql.install_as_MySQLdb() from django.db import models# Create your models here.class Book(models.Model):title = models.CharField(max_length=32)price = models.DecimalField(decimal_places=1, max_digits=6)publish = models.ForeignKey(to='Publish')author = models.ManyToManyField(to='Author', through='Book2Author', through_fields=('book', 'author'))class Publish(models.Model):name = models.CharField(max_length=32)addr = models.CharField(max_length=64, null=True)class Author(models.Model):name = models.CharField(max_length=32)age = models.IntegerField()class Book2Author(models.Model):book = models.ForeignKey(to='Book')author = models.ForeignKey(to='Author')

app01新建MySer.py

# 先創建一個BookSer序列化類 from rest_framework import serializersclass BookSer(serializers.Serializer):id = serializers.CharField()title = serializers.CharField()publish = serializers.CharField()author = serializers.CharField()

app01視圖函數views.py中

from django.shortcuts import render,HttpResponse,redirect from app01.MySer import BookSer from rest_framework.response import Response from rest_framework.views import APIView from app01 import models# Create your views here.class Books(APIView):response = {'code': 100, 'msg': '查詢成功'}def get(self, request):books = models.Book.objects.all()books_ser = BookSer(instance=books, many=True)return Response(books_ser.data)

配路由：

from django.conf.urls import url from django.contrib import admin from app01 import viewsurlpatterns = [url(r'^admin/', admin.site.urls),url(r'^books/', views.Books.as_view()), ]

（通過NaviCat創建圖書數據，用于查詢…）

使用Postman發送get請求，獲取到數據庫中所有圖書信息
可以看出一對多和多對多的外鍵字段顯示的是對象名字，下面進一步使用序列化，讓信息顯示更完善

-source：可以指定字段（name publish.name），可以指定方法-SerializerMethodField搭配方法使用（get_字段名字） publish_detail=serializers.SerializerMethodField(read_only=True) def get_publish_detail(self,obj):return {'name':obj.publish.name,'city':obj.publish.city}

更新版本BookSer

from rest_framework import serializersclass BookSer(serializers.Serializer):id = serializers.CharField()title = serializers.CharField()publish = serializers.CharField(source='publish.name')author = serializers.SerializerMethodField()def get_author(self, obj):authors = []for author_obj in obj.author.all():authors.append({'name': author_obj.name, 'age': author_obj.age})return authors

補充：

-read_only:反序列化時，不傳
-write_only：序列化時，不顯示

以上是序列化的一種方式

下面看看序列化的另外一種方式：ModelSerializers：指定了表模型

class Meta:model=表模型#要顯示的字段fields=('__all__')fields=('id','name')#要排除的字段exclude=('name')#深度控制depth=1-重寫某個字段在Meta外部，重寫某些字段，方式同Serializers # 序列化方式二： class BookSer(serializers.ModelSerializer):class Meta:model = models.Bookfields = ('__all__')

如果只想取其中幾個字段，可以進行指定：

# 序列化方式二： class BookSer(serializers.ModelSerializer):class Meta:model = models.Bookfields = ['id', 'title']# fields = ('__all__')

剛才看到__all__，序列化所有字段，查詢到的數據里面publish和author都是對應id值，如果需要獲取到對應publish和author的關聯信息，可以在BookSer內，Meta外重新寫字段，方式同serializers

# 序列化方式二： class BookSer(serializers.ModelSerializer):class Meta:model = models.Book# fields = ['id', 'title']fields = ('__all__')publish = serializers.CharField(source='publish.name')author = serializers.SerializerMethodField()def get_author(self, obj):authors = []for author_obj in obj.author.all():authors.append({'name': author_obj.name, 'age': author_obj.age})return authors

改進：

class AuthorSer(serializers.Serializer):id = serializers.CharField()name = serializers.CharField()age = serializers.CharField()# 序列化方式二改進： class BookSer(serializers.ModelSerializer):class Meta:model = models.Book# fields = ['id', 'title']fields = ('__all__')publish = serializers.CharField(source='publish.name')author = serializers.SerializerMethodField()def get_author(self, obj):ret = AuthorSer(obj.author.all(), many=True) return ret.data

通過post請求新增數據：
對數據進行新增使用反序列化實現，這里反序列化有2種情況進行新增：

使用繼承了Serializers序列化類的對象，反序列化(需重寫create方法)

from django.db import models# Create your models here.class User(models.Model):name = models.CharField(max_length=32)password = models.CharField(max_length=64)choices = (('1', 'Super_Admin'), ('2', 'General_Admin'), ('3', 'General_User') )user_type = models.CharField(max_length=6, choices=choices, default='3')class Book(models.Model):title = models.CharField(max_length=32)price = models.DecimalField(decimal_places=1, max_digits=6)publish = models.ForeignKey(to='Publish', null=True)author = models.ManyToManyField(to='Author')class Publish(models.Model):name = models.CharField(max_length=32)addr = models.CharField(max_length=64, null=True)class Author(models.Model):name = models.CharField(max_length=32)age = models.IntegerField() class Book(APIView):def post(self, request):response = {'code': 100, 'msg': '新增成功'}# 使用繼承了Serializers序列化類的對象，反序列化book = BookSer(data=request.data)if book.is_valid():# 清洗通過的數據,需要在MySer.py中重寫createbook.create(book.validated_data)return Response(response) # MySer.pyclass BookSer(serializers.Serializer):# read_only 反序列化的時候，該字段不傳# 這里id可以不傳自增，publish、author不傳，當然需要在models里面把不傳字段設置為null=True# author多對多字段不能設置null=Trueid = serializers.CharField(read_only=True) title = serializers.CharField()price = serializers.CharField()publish = serializers.CharField(source='publish.id', read_only=True)author = serializers.SerializerMethodField(read_only=True)def get_author(self, obj):ret = AuthorSer(obj.author.all(), many=True)return ret.data# 重寫create方法，才能在使用Serializer發序列化方法進行新增數據def create(self, validated_data):res = models.Book.objects.create(**validated_data)return res

使用繼承了ModelSerializers序列化類的對象，反序列化

from django.db import models# Create your models here.class User(models.Model):name = models.CharField(max_length=32)password = models.CharField(max_length=64)choices = (('1', 'Super_Admin'), ('2', 'General_Admin'), ('3', 'General_User') )user_type = models.CharField(max_length=6, choices=choices, default='3')class Book(models.Model):title = models.CharField(max_length=32)price = models.DecimalField(decimal_places=1, max_digits=6)publish = models.ForeignKey(to='Publish', null=True)author = models.ManyToManyField(to='Author')class Publish(models.Model):name = models.CharField(max_length=32)addr = models.CharField(max_length=64, null=True)class Author(models.Model):name = models.CharField(max_length=32)age = models.IntegerField() class BookSer(serializers.ModelSerializer):class Meta:model = models.Bookfields = "__all__" class Book(APIView):def post(self, request):response = {'code': 100, 'msg': '新增成功'}# 使用繼承了ModelSerializers序列化類的對象，反序列化book_ser = BookSer(data=request.data)if book_ser.is_valid():book_ser.save()else:response['error'] = book_ser.errors['name'][0]return Response(response)

使用ModelSerializer反序列化save數據后，多對多關聯的那張表也會自動關聯產生新的數據。

局部校驗和全局校驗

# MySer.pyfrom rest_framework.exceptions import ValidationError class BookSer(serializers.ModelSerializer):class Meta:model = models.Bookfields = "__all__"def validate_title(self, value):if value.startswith('sb'):raise ValidationError('不能以sb開頭')return valuedef validate(self, attrs):title = attrs.get('title')price = attrs.get('price')if title.startswith('禁書') or int(price) <= 15:raise ValidationError('書名或價格不正常')return attrs

總結：

-反序列化的校驗
-validate_字段名(self,value):
-如果校驗失敗，拋出ValidationError（拋出的異常信息需要去bookser.errors中取）
-如果校驗通過直接return value
-validate(self,attrs)
-attrs所有校驗通過的數據，是個字典
-如果校驗失敗，拋出ValidationError
-如果校驗通過直接return attrs

總結

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