Python对象转换为json

Python中内置了json库,用起来超级方便,json现在以成为开发的必备。

json的api有下面4个:

json.loads() json转换为dict
json.dumps() dict转换为json

json.load() json文件转换为dict
json.dump() dict转换为json文件 person.json

注意:dict也可以是类对象

dict转换为json

import json

person = {
    'name': 'jack',
    'age': 15,
    'email': 'jack@litets.com'
}


print('dict:', person)

person_json = json.dumps(person) # 转换为json

print('json:', person_json)

输出:

dict {'name': 'jack', 'age': 15, 'email': 'jack@litets.com'}
json {"name": "jack", "age": 15, "email": "jack@litets.com"}

json转换为dict

import json
person_dict = json.loads('{"name": "jack", "age": 15, "email": "jack@litets.com"}')

print('person dict:', person_dict)

输出:

person dict: {'name': 'jack', 'age': 15, 'email': 'jack@litets.com'}

类对象转换为json

import json

class Person:

    def __init__(self, name, age, email):
        self.name = name
        self.age = age
        self.email = email


person = Person('tom', 38, 'tom@litets.com')

person_json = json.dumps(person.__dict__)

print('person json:', person_json)

输出:

person json: {"name": "tom", "age": 38, "email": "tom@litets.com"}

json.dumps()不能直接传递一个对象实例否则回报TypeError: Object of type Person is not JSON serializable错误 为了避免这个错误,我们需要修改:

import json
class Person:

    def __init__(self, name, age, email):
        self.name = name
        self.age = age
        self.email = email

# 将person转换为dict
def convert2json(person):
    return {
        'name': person.name,
        'age': person.age,
        'email': person.email
    }

person = Person('tom', 38, 'tom@litets.com')

# 第二个参数传递转换函数,或者使用default=lambda o: o.__dict__
person_json = json.dumps(person, default=convert2json)

print('person json:', person_json)

json转换为类对象

import json

class Person:

    def __init__(self, name, age, email):
        self.name = name
        self.age = age
        self.email = email


def convert2json(dict_json):
    return Person(dict_json['name'], dict_json['age'], dict_json['email'])


person = json.loads('{"name": "tom", "age": 38, "email": "tom@litets.com"}', object_hook=convert2json)

print('person:', person)

输出:

person: <__main__.Person object at 0x10a7230b8>

loads函数只能将json转换为字典,需要我们自己转换为对象。

dict/对象转换为json文件

import 
person = {"name": "tom", "age": 38, "email": "tom@litets.com"}

with open('person.json', 'w') as f:
    json.dump(person, f)

当前目录下会多一个person.json文件,内容是:

{"name": "tom", "age": 38, "email": "tom@litets.com"}

将json文件转换为dict/对象

import json
with open('person.json', 'r') as f:
    print(json.load(f))

输出:

{'name': 'tom', 'age': 38, 'email': 'tom@litets.com'}
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