一、定义
- json全称：javascript object notation
- 前后端交互的枢纽：后端通过将程序产生的字典转化成json格式的json字符串(串)，然后通过网络传输，给到前端，前端解析json文件，完成数据交互
二、python字典与json字符串相互转换
1. python字典 ------> json字符串：dumps
- ensure_ascii：默认为True。如果ensure_ascii为False, 那么写入的字符串中可以包含非ASCII字符
import jsondic = {"name": "Tom", "age": 18, "hobby": "篮球", 1: False, 2: None}s = json.dumps(dic, ensure_ascii=False)print(s) ?# {"name": "Tom", "age": 18, "hobby": "篮球", "1": false, "2": null}2. json字符串 ------> python字典：loads
s = ‘{"name": "Tom", "age": 18, "hobby": "篮球", "1": false, "2": null}‘dic = json.loads(s)print(dic) ??# {‘name‘: ‘Tom‘, ‘age‘: 18, ‘hobby‘: ‘篮球‘, ‘1‘: False, ‘2‘: None}三、读、写json文件
1. dump
将python字典转换成json字符串，并写入文件中
- indent：缩进
import jsondic = {"name": "Tom", "age": 18, "hobby": "篮球", 1: False, 2: None}f = open("1.json", "w", encoding="utf-8") ?# 把对象打散成json写入到文件中json.dump(dic, f, ensure_ascii=False, indent=4)f.close()
结果：
2. load
- 读取json文件，并解析成字典
import jsonf = open("1.json", encoding="utf-8")dic = json.load(f)f.close()print(dic) ?# {‘name‘: ‘Tom‘, ‘age‘: 18, ‘hobby‘: ‘篮球‘, ‘1‘: False, ‘2‘: None}四、读、写多个json字符串
1. 问题
我们可以向同一文件中写入多个json字符串,但是json文件中内容是一行内容。此时读取时无法读取。
import jsonlst = [{"a": 1}, {"b": 2}, {"c": 3}]f = open("2.json", "w")for el in lst: ???json.dump(el, f)f.close()
结果：
f = open("2.json")dic = json.load(f)结果：json.decoder.JSONDecodeError: Extra data: line 1 column 9 (char 8)2. 解决方案
改用dumps和loads，对每一行分别做处理
import jsonlst = [{"a": 1}, {"b": 2}, {"c": 3}]f = open("2.json", "w")for el in lst: ???s = json.dumps(el) + "\n" ???f.write(s)f.close()
结果：
f = open("2.json")for line in f: ???dic = json.loads(line.strip()) ???print(dic)f. close()
结果：
{‘a‘: 1}
{‘b‘: 2}
{‘c‘: 3}
五、json处理类
1. 将类转换成json字符串
import jsonclass Person(object): ???def __init__(self, name, age): ???????self.name = name ???????self.age = agep = Person("Tom", 18)def func(obj): ???return {"name": obj.name, "age": obj.age}s = json.dumps(p, default=func)print(s) ?# {"name": "Tom", "age": 18}2. 将json字符串赋给类
class Person(object): ???def __init__(self, name, age): ???????self.name = name ???????self.age = ages = ‘{"name": "Tom", "age": 18}‘def func(dic): ???return Person(dic["name"], dic["age"])p = json.loads(s, object_hook=func)print(p.name, p.age) ?# Tom ?18json
原文地址：https://www.cnblogs.com/ipython-201806/p/9964571.html