将多个类序列化为JSON

import json

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def to_json(self):
        return {
            'name': self.name,
            'age': self.age
        }

class Address:
    def __init__(self, city, country):
        self.city = city
        self.country = country
    
    def to_json(self):
        return {
            'city': self.city,
            'country': self.country
        }

class Employee:
    def __init__(self, person, address):
        self.person = person
        self.address = address
    
    def to_json(self):
        return {
            'person': self.person.to_json(),
            'address': self.address.to_json()
        }

# 创建对象
person = Person('John', 30)
address = Address('New York', 'USA')
employee = Employee(person, address)

# 序列化为JSON字符串
json_str = json.dumps(employee.to_json())
print(json_str)