Json记录并将其保存到文件中

Question

我有一个小应用程序，它从数据库中查询记录，需要将其转换为JSON，并且必须将其存储在本地文件中。

我已经走到这一步了：

models.py

from flask.ext.sqlalchemy import SQLAlchemy
from app import app

app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://ajay:12345@localhost/fusion'
db = SQLAlchemy(app)

class User(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    time = db.Column(db.DateTime, default=None, index=True)

views.py

from models import User
from flask import render_template
from app import app
from json import dumps
from sqlalchemy.orm import class_mapper

def serialize(model):
    columns = [c.key for c in class_mapper(model.__class__).columns]
    return dict((c, getattr(model, c)) for c in columns)

@app.route('/')
def index():
    data = [ serialize(user) for user in User.query.all() ]
    file = open('data.json','w')
    json_users = dumps(data)
    file.write(json_users)
    file.close()
    return render_template('index.html', users=json_users)

我得到的错误是：

TypeError: datetime.datetime(2011, 10, 16, 15, 14, 57) is not JSON serializable

下一步怎么做？

Answer 1

您必须将 time 从 User 类转换为字符串

编辑：

我有根据的猜测

time = db.Column(db.DateTime, default=None, index=True).ctime()