标签：elf any www. 字符 man author false 循环 组织
http://www.cnblogs.com/yuanchenqi/articles/8719520.html
from django.db import models # Create your models here. class Book(models.Model): title = models.CharField(max_length=32) price = models.IntegerField() pub_date = models.DateField() publish = models.ForeignKey("Publish", on_delete=models.CASCADE) authors = models.ManyToManyField("Author") def __str__(self): return self.title class Publish(models.Model): name = models.CharField(max_length=32) email = models.EmailField() def __str__(self): return self.name class Author(models.Model): name = models.CharField(max_length=32) age = models.IntegerField() def __str__(self): return self.name
urls.py:
from django.contrib import admin
from django.urls import path
from app01 import views
urlpatterns = [
path(‘admin/‘, admin.site.urls),
path(‘publishes/‘, views.PublishView.as_view())
]
from django.shortcuts import render, HttpResponse
from django.views import View
from .models import Publish
import json
class PublishView(View):
def get(self, request):
# QuerySet对象不能进行json序列化
# 方式1：values(*field):调用者是queryset对象，运行后得到的并不是一系列model的实例化对象，而是一个可迭代的字典序列
# 再使用list()方法强转为列表，组成列表里面放字典的数据结构
publish_list = list(Publish.objects.all().values("name", "email"))
return HttpResponse(json.dumps(publish_list))
def post(self, request):
pass
注意：
调用者是queryset对象，运行后得到的并不是一系列model的实例化对象，而是一个可迭代的字典序列:
<QuerySet [{‘name‘: ‘橘子出版社‘, ‘email‘: ‘456@qq.com‘}, {‘name‘: ‘苹果出版社‘, ‘email‘: ‘123@qq.com‘}]>
将序列强行转化为数组：
[{‘name‘: ‘橘子出版社‘, ‘email‘: ‘456@qq.com‘}, {‘name‘: ‘苹果出版社‘, ‘email‘: ‘123@qq.com‘}]
json.dumps 用于将 Python 对象编码成 JSON 字符串。以下是python 原始类型向 json 类型的转化对照表：
from django.views import View
from .models import Publish
import json
class PublishView(View):
def get(self, request):
# QuerySet对象不能进行json序列化
# 方式2：
publish_list = Publish.objects.all()
temp = []
for obj in publish_list:
temp.append({
"name": obj.name,
"name": obj.email
})
print(temp) # [{‘name‘: ‘456@qq.com‘}, {‘name‘: ‘123@qq.com‘}]
return HttpResponse(json.dumps(temp))
def post(self, request):
pass
这样写的问题是有多少字段就要加多少个字段，而且如果不知道是哪张表或者有哪些字段，就无法构建数据。
model_to_dict是用于将model对象转换为字典的方法。
from django.views import View
from .models import Publish
import json
class PublishView(View):
def get(self, request):
# QuerySet对象不能进行json序列化
# 方式2：
from django.forms.models import model_to_dict
publish_list = Publish.objects.all()
temp = []
for obj in publish_list:
temp.append(model_to_dict(obj))
print(temp) # [{‘name‘: ‘456@qq.com‘}, {‘name‘: ‘123@qq.com‘}]
return HttpResponse(json.dumps(temp))
在pycharm的python console测试：
>>>from django.forms.models import model_to_dict
>>>from app01 import models
>>>print(models)
<module ‘app01.models‘ from ‘/Users/hqs/PycharmProjects/restDemo/app01/models.py‘>
>>>obj = models.Publish.objects.all()
>>>print(obj)
<QuerySet [<Publish: 橘子出版社>, <Publish: 苹果出版社>]>
>>>obj = models.Publish.objects.filter(pk=2).first()
>>>obj # obj是一个model对象
<Publish: 橘子出版社>
>>>model_to_dict(obj)
{‘id‘: 2, ‘name‘: ‘橘子出版社‘, ‘email‘: ‘456@qq.com‘}
由此可见有几个字段就转化为几个键值对的字典。
serializers是django的序列化组件。
from django.views import View
from .models import Publish
import json
class PublishView(View):
def get(self, request):
# QuerySet对象不能进行json序列化
# 方式3：
from django.core import serializers
publish_list = Publish.objects.all()
ret = serializers.serialize("json", publish_list)
return HttpResponse(json.dumps(ret))
def post(self, request):
pass
注意：
def serialize(format, queryset, **options):
"""
Serialize a queryset (or any iterator that returns database objects) using
a certain serializer.
"""
s = get_serializer(format)()
s.serialize(queryset, **options)
return s.getvalue()
传递给 serialize 方法的参数有二：一个序列化目标格式，另外一个是序列化的对象QuerySet. (事实上，第二个参数可以是任何可迭代的Django Model实例，但它很多情况下就是一个QuerySet).
"[{\"model\": \"app01.publish\", \"pk\": 2, \"fields\": {\"name\": \"\\u6a58\\u5b50\\u51fa\\u7248\\u793e\", \"email\": \"456@qq.com\"}}, {\"model\": \"app01.publish\", \"pk\": 3, \"fields\": {\"name\": \"\\u82f9\\u679c\\u51fa\\u7248\\u793e\", \"email\": \"123@qq.com\"}}]"
from django.views import View
from .models import Publish
import json
from rest_framework import serializers
class PublishSerializers(serializers.Serializer):
"""为QuerySet做序列化"""
name = serializers.CharField()
email = serializers.CharField()
class PublishView(View):
def get(self, request):
# 方式4：
publish_list = Publish.objects.all()
ret = PublishSerializers(publish_list, many=True) # 描述是model对象还是QuerySet True：queryset
return HttpResponse(json.dumps(ret))
def post(self, request):
pass
注意：
>>>from app01.views import PublishSerializers
>>>publish_list = models.Publish.objects.all()
>>>PublishSerializers(publish_list, many=True) # 描述是model对象还是QuerySet
PublishSerializers(<QuerySet [<Publish: 橘子出版社>, <Publish: 苹果出版社>]>, many=True):
name = CharField()
email = CharField()
>>>ps = PublishSerializers(publish_list, many=True)
>>>ps.data
[OrderedDict([(‘name‘, ‘橘子出版社‘), (‘email‘, ‘456@qq.com‘)]), OrderedDict([(‘name‘, ‘苹果出版社‘), (‘email‘, ‘123@qq.com‘)])]
在序列化时，第一个参数传递要序列化的对象，第二个参数many是向组件声明到底是model对象还是QuerySet。
many=True：QuerySet many=False：model对象
标签：elf any www. 字符 man author false 循环 组织
原文地址：https://www.cnblogs.com/xiugeng/p/9572089.html
