最近使用开辟的过程中出现了一个小问题，顺便记录一下原因和方法--格式资料

最近，给自己开辟的软件平台开辟第三方调用的API，如果返回结果集是json格式，其他语言开辟就绝对便利一些，网上找了好多资料没有找到特殊合适的，最后下决心根据网上的资料转变自己写一个通用的。

此方法，主要应用场景是，Python 数据库框架 sqlalchemy 查询结果，转化成json格式。

# -*- coding: utf-8 -*-
import os
import json
import threadingfrom xml.dom import minidom
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, scoped_session
from sqlalchemy import (create_engine,MetaData,Column,Integer,String)
from sqlalchemy import func
from sqlalchemy.sql.expression import and_, or_
from sqlalchemy import Table, Column, Integer, String, Text, DateTime, MetaData, ForeignKey, Boolean
from datetime import datetime
import time,uuid,reBase = declarative_base()#主机模型
class VirtualMachineContainer(Base):__tablename__ = 'virtual_machine_containers'id = Column(Integer, primary_key = True)hostname = Column(String(255))uuid = Column(String(255))address = Column(String(255))port = Column(Integer)status = Column(String(255))owner_id = Column(Integer)group_id = Column(Integer)cluster_id = Column(Integer)running_time = Column(Integer)cpu_type = Column(String(255))cpu_num = Column(String(255))cpu_usage = Column(String(255))mem_total = Column(String(255))mem_free = Column(String(255))disk_device = Column(String(255))disk_total = Column(String(255))disk_free = Column(String(255))nics_num = Column(Integer)net_ifname = Column(String(255))net_tx = Column(String(255))net_rx = Column(String(255))vm_name = Column(String(255))vm_state = Column(String(255))vcpu_usage = Column(String(255))vmem_total = Column(String(255))vmem_free = Column(String(255))vdisk_read = Column(String(255))vdisk_write = Column(String(255))vif_tx = Column(String(255))vif_rx = Column(String(255))field_metadata = Column('metadata', String(255))created_at = Column(DateTime, default=datetime.now)updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)vm_uuid = Column(Text)capability = Column(String(255))vdisk_names = Column(String(255))vif_names = Column(String(255))all_pair_ping = Column(Text)vnc_port = Column(String(255))vm_cnt = Column(Integer)respool_cnt = Column(String(255))reserved = Column(String(255))host_desc = Column(Text)host_vendor_name = Column(String(255))host_type = Column(String(255))oper_system_vendor_name = Column(String(255))oper_system_name = Column(String(255))uuid_bios = Column(String(255))dns = Column(String(255))cpu_core_num = Column(String(255))cpu_thread_num = Column(String(255))diskarray_num = Column(String(255))datacenter_id = Column(Integer, ForeignKey('data_centers.id'))user_name = Column(String(255))password = Column(String(255))status_flag = Column(Integer(1))hardware_id = Column(String(16))def get_Session():#engine = create_engine('mysql://root:root@172.30.36.7/ivcs_portal?charset=utf8')engine = create_engine('mysql://root:@172.30.36.7/ivcs_portal?charset=utf8')Base.metadata.create_all(engine)Session =sessionmaker( autocommit=False, autoflush=False, bind=engine)return Session
from sqlalchemy.ext.declarative import DeclarativeMeta
class AlchemyEncoder(json.JSONEncoder):def default(self, obj):if isinstance(obj.__class__, DeclarativeMeta):# an SQLAlchemy classfields = {}for field in [x for x in dir(obj) if not x.startswith('_') and x != 'metadata']:data = obj.__getattribute__(field)try:if isinstance(data, datetime): data=data.strftime('%Y-%m-%d %H:%M:%S') json.dumps(data) # this will fail on non-encodable values, like other classesfields[field] = dataexcept TypeError:fields[field] = None# a json-encodable dictreturn fieldsreturn json.JSONEncoder.default(self, obj)
def new_alchemy_encoder():_visited_objs = []class AlchemyEncoder(json.JSONEncoder):def default(self, obj):if isinstance(obj.__class__, DeclarativeMeta):# don't re-visit selfif obj in _visited_objs:return None_visited_objs.append(obj)# an SQLAlchemy classfields = {}for field in [x for x in dir(obj) if not x.startswith('_') and x != 'metadata']:data = obj.__getattribute__(field)try:if isinstance(data, datetime): data=data.strftime('%Y-%m-%d %H:%M:%S') json.dumps(data) # this will fail on non-encodable values, like other classesfields[field] = dataexcept TypeError:fields[field] = Nonereturn fieldsreturn json.JSONEncoder.default(self, obj)return AlchemyEncoderdef testjson():session=get_Session()()vmcs = session.query(VirtualMachineContainer).all()try:Hosts =[]for vmc in vmcs:#print json.dumps(vmc, cls=AlchemyEncoder)Hosts.append(vmc)print json.dumps(Hosts, cls=new_alchemy_encoder(), check_circular=False)except Exception, e:print e  if __name__ == '__main__':testjson()

文章结束给大家分享下程序员的一些笑话语录： 人脑与电脑的相同点和不同点，人脑会记忆数字，电脑也会记忆数字；人脑会记忆程序，电脑也会记忆程序，但是人脑具有感知能力，这种能力电脑无法模仿，人的记忆会影响到人做任何事情，但是电脑只有程序软件。比尔还表示，人脑与电脑之间最重要的一个差别就是潜意识。对于人脑存储记忆的特别之处，比尔表示，人脑并不大，但是人脑重要的功能是联络，人脑会把同样的记忆存储在不同的地方，因此记忆读取的速度就不相同，而这种速度取决于使用的频率和知识的重要性。人脑的记忆存储能力会随着年龄增长而退化，同时记忆的质量也会随着年龄退化。经典语录网