shutil模块主要用于文件夹的操作。其中copytree用来对文件夹进行复制，但是比较遗憾的是，如果目标文件已经存在的话，该函数就会报错抛异常了，非常地不给力。求人不如求已，看到帮助文档中有此方法的源码，就修改了一下，使其默认可以支持文件和文件夹的覆盖。
import os import os.path import shutil def copytree(src, dst, symlinks=False): names = os.listdir(src) if not os.path.isdir(dst): os.makedirs(dst) errors = [] for name in names: srcname = os.path.join(src, name) dstname = os.path.join(dst, name) try: if symlinks and os.path.islink(srcname): linkto = os.readlink(srcname) os.symlink(linkto, dstname) elif os.path.isdir(srcname): copytree(srcname, dstname, symlinks) else: if os.path.isdir(dstname): os.rmdir(dstname) elif os.path.isfile(dstname): os.remove(dstname) shutil.copy2(srcname, dstname) # XXX What about devices, sockets etc.? except (IOError, os.error) as why: errors.append((srcname, dstname, str(why))) # catch the Error from the recursive copytree so that we can # continue with other files except OSError as err: errors.extend(err.args[0]) try: copystat(src, dst) except WindowsError: # can't copy file access times on Windows pass except OSError as why: errors.extend((src, dst, str(why))) if errors: raise Error(errors) if __name__ == '__main__': copytree('E:/book', 'E:/newbook')
