如何使用Python对比两个JSON文件并将可读差异写入Output.json

方案1：使用deepdiff第三方库（推荐，代码量少、差异维度清晰） #

• 先安装依赖包：pip install deepdiff
• 完整实现代码：

import json
from deepdiff import DeepDiff

# 读取两个待比对JSON文件
with open("File1.json", "r", encoding="utf-8") as f1:
    json_data1 = json.load(f1)
with open("File2.json", "r", encoding="utf-8") as f2:
    json_data2 = json.load(f2)

# 生成结构化差异，配置参数保障可读性
diff_result = DeepDiff(json_data1, json_data2, ensure_ascii=False)

# 格式化输出差异到目标文件
with open("Output.json", "w", encoding="utf-8") as out_f:
    json.dump(diff_result, out_f, indent=2, ensure_ascii=False)

• 输出差异默认包含清晰的分类字段：
  • dictionary_item_added：File2 比 File1 新增的键值对
  • dictionary_item_removed：File2 比 File1 删减的键值对
  • values_changed：同路径下的数值变动，会同时标注旧值和新值
  • list_added/list_removed：数组类字段的元素增删内容

方案2：纯原生Python实现（无需第三方依赖） #

如果运行环境不能安装额外包，可以使用递归比对的原生实现：

import json

def compare_json(a, b, path=""):
    diff = {}
    # 比对字典类型
    if isinstance(a, dict) and isinstance(b, dict):
        for key in a.keys() - b.keys():
            full_path = f"{path}.{key}" if path else key
            diff[f"removed:{full_path}"] = a[key]
        for key in b.keys() - a.keys():
            full_path = f"{path}.{key}" if path else key
            diff[f"added:{full_path}"] = b[key]
        for key in a.keys() & b.keys():
            sub_path = f"{path}.{key}" if path else key
            sub_diff = compare_json(a[key], b[key], sub_path)
            if sub_diff:
                diff.update(sub_diff)
    # 比对数组类型
    elif isinstance(a, list) and isinstance(b, list):
        if len(a) != len(b):
            diff[f"length_changed:{path}"] = f"旧长度：{len(a)}，新长度：{len(b)}"
        for idx, (item_a, item_b) in enumerate(zip(a, b)):
            sub_path = f"{path}[{idx}]"
            sub_diff = compare_json(item_a, item_b, sub_path)
            if sub_diff:
                diff.update(sub_diff)
    # 比对基础类型值
    else:
        if a != b:
            diff[f"value_changed:{path}"] = {"old_value": a, "new_value": b}
    return diff

if __name__ == "__main__":
    with open("File1.json", "r", encoding="utf-8") as f1, open("File2.json", "r", encoding="utf-8") as f2:
        j1, j2 = json.load(f1), json.load(f2)
    res = compare_json(j1, j2)
    with open("Output.json", "w", encoding="utf-8") as out_f:
        json.dump(res, out_f, indent=2, ensure_ascii=False)

内容的提问来源于stack exchange，提问作者Noman