python3 json.dumps报错int64 is not JSON serializable怎么解决_Python

错误场景

在使用json.dumps时，出现问题：

typeerror: object of type int64 is not json serializable

问题分析

python3中没有int64这个数据类型，所有的整型都是int
报错里的int64指的是<class ‘numpy.int64’>，所以很有迷惑性
同样的还会出现 typeerror: object of type float32/float64 is not json serializable

解决方案1

typeerror: object of type int64 is not json serializable

def default_dump(obj):
    """convert numpy classes to json serializable objects."""
    if isinstance(obj, (np.integer, np.floating, np.bool_)):
        return obj.item()
    elif isinstance(obj, np.ndarray):
        return obj.tolist()
    else:
        return obj
        
json.dumps(new_config,ensure_ascii=false, default=default_dump)

解决方案2

import json

class jsonencoder(json.jsonencoder):
    """convert numpy classes to json serializable objects."""

    def default(self, obj):
        if isinstance(obj, (np.integer, np.floating, np.bool_)):
            return obj.item()
        elif isinstance(obj, np.ndarray):
            return obj.tolist()
        else:
            return super(jsonencoder, self).default(obj)
        
json.dumps(new_config,ensure_ascii=false, cls=jsonencoder)

问题延伸：针对flask jsonify() 序列化错误：

flask < 2.2

import datatime
from flask import flask as _flask
from flask.json import jsonencoder as _jsonencoder

class flaskjsonencoder(_jsonencoder):
    """重载flask的json encoder, 确保jsonfy()能解析numpy的json"""

    def default(self, obj):
        if isinstance(obj, (np.integer, np.floating, np.bool_)):
            return obj.item()
        elif isinstance(obj, np.ndarray):
            return obj.tolist()
        elif isinstance(obj, (datetime.datetime, datetime.timedelta)):
            return obj.__str__()
        else:
            return super(flaskjsonencoder, self).default(obj)

class flask(_flask):
    """重载flask的jsonencoder, 确保能解析numpy的json"""
    json_encoder = flaskjsonencoder
    
app = flask(__name__)

flask >= 2.2

import datatime
from flask import flask as _flask
from flask.json.provider import defaultjsonprovider, _default as flaskdefault
        
class flaskjsonprovider(defaultjsonprovider):
   """重载flask的json encoder, 确保jsonfy()能解析numpy的json"""
    
    @staticmethod
    def _default(obj):
        if isinstance(obj, (np.integer, np.floating, np.bool_)):
            return obj.item()
        elif isinstance(obj, np.ndarray):
            return obj.tolist()
        elif isinstance(obj, (datetime.datetime, datetime.timedelta)):
            return obj.__str__()
        else:
            return flaskdefault(obj)
	
	default = _default


class flask(_flask):
    """重载flask的json_provider_class, 确保能解析numpy的json"""
    json_provider_class = flaskjsonprovider
    
app = flask(__name__)