python 连接mongo 及解决json.dumps()中文编码

from __future__ import unicode_literals
import pymongo
import json
conn = pymongo.MongoClient(host='127.0.0.1',port=27017)
db = conn['first_db']
# print(db.collection_names())
conection = db['TestItem']
dict = {}
for i in conection.find():
    for a,b,c in zip(i['author'],i['Tages'],i['content']):
        dict['作者'] = a
        dict['标签'] = b
        dict['作品'] = c
        # print(dict)
        print (json.dumps(dict, ensure_ascii=False))
        fp = open('output.txt', 'a+',encoding='utf8')
        fp.write(json.dumps(dict, ensure_ascii=False))
        fp.close()