Windows Server 2012运行Python目录遍历代码报FileNotFoundError[WinError3]求助

问题描述 #

我编写了如下代码，用于遍历指定路径下的所有文件、子文件夹及各级目录，但是在Windows Server 2012设备上运行时持续抛出FileNotFoundError[WinError3]报错。值得注意的是，我在Mac设备上运行同一段代码时也出现过相同报错，将follow_symlinks参数设置为False后报错就消失了，但该配置在Windows Server 2012环境下没有解决问题，恳请各位帮忙排查代码存在的问题。

原始代码 #

from pathlib import Path
import csv
import os
import time
from datetime import datetime

class File:
    def __init__(self, folder_path):
        self.folder_path = Path(folder_path)
   
    def folders(self):
        return [folder for folder in self.folder_path.iterdir() if folder.is_dir()]
   
    def summary(self):
        errors = []
        data_table = []
        folders =  self.folders()
        for folder in folders:
            total=0
            count = 0
            files = folder.glob('**/*')
            for file in files :
                try:
                    total+=(os.stat(file, follow_symlinks=False).st_size)
                    count+=1
                except OSError as e:
                    errors.append(f'Error with file {file} in folder {folder} Error-->{e}')      
                    lm_date = datetime.strftime(datetime.strptime(time.ctime(os.stat(folder).st_mtime),
                                                                  '%a %b %d %H:%M:%S %Y'), '%d-%b-%Y')
                    data_table.append({'Path':folder, 'Size in MB':f'{total/1048576}', 'File Count':count,
                                       'Last Modifed Date':lm_date})
            lm_date = datetime.strftime(datetime.strptime(time.ctime(os.stat(folder).st_mtime),
                                                                  '%a %b %d %H:%M:%S %Y'), '%d-%b-%Y')
            data_table.append({'Path':folder, 'Size in MB':f'{total/1048576}', 'File Count':count,
                                       'Last Modifed Date':lm_date})
        return {'data':data_table, 'error':errors}  

    def csv_export(self, file_path):
        data_list =  self.summary()['data']
        headers = data_list[0].keys()
        with open(file_path, 'w') as fp:
             writer = csv.DictWriter(fp, headers)
             writer.writeheader()
             try:
                 for data in data_list:
                        writer.writerow(data)
                 print(f'file saved to location: {os.path.join(os.getcwd(), file_path)}')
             except OSError as e:
                print(f'Error exporting data file {e}')

问题排查与修复 #

核心问题原因 #

你遇到的WinError3报错是Windows系统特有的路径长度限制问题：Windows Server 2012默认开启260字符的路径长度上限，当遍历到路径总长度超过260的文件/文件夹时，系统会直接抛出路径不存在的错误，和符号链接无关，所以设置follow_symlinks自然不会生效。

另外你的代码还有两处逻辑问题：

• 捕获异常时错误地把不完整的统计数据追加到了结果列表里，会导致同一个文件夹产生多条重复的无效记录
• 重复调用os.stat(folder)没有做异常捕获，遇到无权限访问的文件夹时也会触发报错
• 时间转换逻辑冗余，time.ctime受系统语言影响，非英文语言的Windows设备上会出现格式匹配错误

修复方案 #

1. **开启Windows长路径支持（可选）
   如果希望全局开启长路径支持，操作步骤如下：

• 按下Win+R输入regedit打开注册表
• 定位到路径HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem
• 找到名为LongPathsEnabled的DWORD值，将值设置为1，重启设备生效

2. **代码层面修复
   无需修改系统设置也可以通过路径前缀兼容长路径，优化后代码如下：

from pathlib import Path
import csv
import os
from datetime import datetime

class FileScanner:
    def __init__(self, folder_path):
        # 路径前加\\?\前缀强制Windows识别最长32767字符的长路径
        raw_path = Path(folder_path).resolve()
        self.folder_path = Path(f'\\\\?\\{raw_path}')
   
    def folders(self):
        folders = []
        for item in self.folder_path.iterdir():
            try:
                if item.is_dir(follow_symlinks=False):
                    folders.append(item)
            except OSError as e:
                print(f"跳过无法访问的目录：{item}, 错误：{e}")
        return folders
   
    def summary(self):
        errors = []
        data_table = []
        folders =  self.folders()
        for folder in folders:
            total=0
            count = 0
            files = folder.glob('**/*')
            for file in files :
                try:
                    if file.is_file(follow_symlinks=False):
                        total += os.stat(file, follow_symlinks=False).st_size
                        count +=1
                except OSError as e:
                    errors.append(f'处理文件 {file} 时出错，所属文件夹 {folder}，错误信息：{e}')
            # 文件夹统计完成后再统一追加记录，避免异常时写入无效数据
            try:
                mtime = folder.stat(follow_symlinks=False).st_mtime
                lm_date = datetime.fromtimestamp(mtime).strftime('%d-%b-%Y')
                data_table.append({
                    'Path': str(folder).replace('\\\\?\\', ''), # 输出时移除长路径前缀
                    'Size in MB': f'{total/1048576:.2f}',
                    'File Count': count,
                    'Last Modifed Date': lm_date
                })
            except OSError as e:
                errors.append(f'读取文件夹 {folder} 元信息失败，错误信息：{e}')
        return {'data':data_table, 'error':errors}  

    def csv_export(self, file_path):
        result = self.summary()
        data_list = result['data']
        if not data_list:
            print("无有效数据可导出")
            return
        headers = data_list[0].keys()
        export_path = Path(file_path).resolve()
        try:
            # newline=''参数避免Windows下生成的CSV出现多余空行，utf-8-sig编码保证中文路径正常显示
            with open(export_path, 'w', newline='', encoding='utf-8-sig') as fp:
                writer = csv.DictWriter(fp, headers)
                writer.writeheader()
                writer.writerows(data_list)
            print(f'文件已保存到：{export_path}')
            if result['error']:
                print(f"本次扫描共遇到{len(result['error'])}个错误，错误列表：")
                for err in result['error']:
                    print(f"- {err}")
        except OSError as e:
            print(f'导出数据文件出错：{e}')

内容的提问来源于stack exchange，提问作者pyzer