我有一个任务要清理大量目录。我想从一个目录开始并删除任何不包含文件的子目录（无论多深）（文件永远不会被删除，只有目录）。如果起始目录不包含文件或子目录，则将被删除。我希望有人能给我指出一些现有的代码，而不是重新发明轮子。我将使用 C# 来完成此操作。
使用C#代码。
static void Main(string[] args)
{
processDirectory(@"c:\temp");
}
private static void processDirectory(string startLocation)
{
foreach (var directory in Directory.GetDirectories(startLocation))
{
processDirectory(directory);
if (Directory.GetFiles(directory).Length == 0 &&
Directory.GetDirectories(directory).Length == 0)
{
Directory.Delete(directory, false);
}
}
}
如果您可以针对 .NET 4.0，您可以使用
Directory方法有：
Directory.EnumerateDirectoriesDirectory.EnumerateFilesDirectory.EnumerateFileSystemEntries使用递归的可能实现：
static void Main(string[] args)
{
DeleteEmptyDirs("Start");
}
static void DeleteEmptyDirs(string dir)
{
if (String.IsNullOrEmpty(dir))
throw new ArgumentException(
"Starting directory is a null reference or an empty string",
"dir");
try
{
foreach (var d in Directory.EnumerateDirectories(dir))
{
DeleteEmptyDirs(d);
}
var entries = Directory.EnumerateFileSystemEntries(dir);
if (!entries.Any())
{
try
{
Directory.Delete(dir);
}
catch (UnauthorizedAccessException) { }
catch (DirectoryNotFoundException) { }
}
}
catch (UnauthorizedAccessException) { }
}
您还提到目录树可能非常深，因此如果您探测的路径太长，您可能会遇到一些异常。
对目前提到的 3 种方法在 C:\Windows 上运行测试 1000 次，结果如下：
GetFiles+GetDirectories:630ms
GetFileSystemEntries:295ms
EnumerateFileSystemEntries.Any:71ms
在空文件夹上运行它会产生以下结果（再次运行 1000 次）：
GetFiles+GetDirectories:131ms
GetFileSystemEntries:66ms
EnumerateFileSystemEntries.Any:64ms
因此，当您检查空文件夹时，EnumerateFileSystemEntries 是迄今为止最好的整体。
这是一个利用并行执行在某些情况下更快完成任务的版本：
public static void DeleteEmptySubdirectories(string parentDirectory){
System.Threading.Tasks.Parallel.ForEach(System.IO.Directory.GetDirectories(parentDirectory), directory => {
DeleteEmptySubdirectories(directory);
if(!System.IO.Directory.EnumerateFileSystemEntries(directory).Any()) System.IO.Directory.Delete(directory, false);
});
}
这是单线程模式下的相同代码：
public static void DeleteEmptySubdirectoriesSingleThread(string parentDirectory){
foreach(string directory in System.IO.Directory.GetDirectories(parentDirectory)){
DeleteEmptySubdirectories(directory);
if(!System.IO.Directory.EnumerateFileSystemEntries(directory).Any()) System.IO.Directory.Delete(directory, false);
}
}
...这里有一些示例代码，您可以使用它来测试场景中的结果：
var stopWatch = new System.Diagnostics.Stopwatch();
for(int i = 0; i < 100; i++) {
stopWatch.Restart();
DeleteEmptySubdirectories(rootPath);
stopWatch.Stop();
StatusOutputStream.WriteLine("Parallel: "+stopWatch.ElapsedMilliseconds);
stopWatch.Restart();
DeleteEmptySubdirectoriesSingleThread(rootPath);
stopWatch.Stop();
StatusOutputStream.WriteLine("Single: "+stopWatch.ElapsedMilliseconds);
}
...这是我的机器针对广域网文件共享上的目录的一些结果。此共享当前只有 16 个子文件夹和 2277 个文件。
Parallel: 1479
Single: 4724
Parallel: 1691
Single: 5603
Parallel: 1540
Single: 4959
Parallel: 1592
Single: 4792
Parallel: 1671
Single: 4849
Parallel: 1485
Single: 4389
用于删除空目录的Powershell脚本:
$items = Get-ChildItem -Recurse
foreach($item in $items)
{
if( $item.PSIsContainer )
{
$subitems = Get-ChildItem -Recurse -Path $item.FullName
if($subitems -eq $null)
{
"Remove item: " + $item.FullName
Remove-Item $item.FullName
}
$subitems = $null
}
}
注意：使用风险自负！
DirectoryInfo.Delete
只删除空目录，你可以写一个简洁的扩展方法
public static void DeleteEmptyDirs(this DirectoryInfo dir)
{
foreach (DirectoryInfo d in dir.GetDirectories())
d.DeleteEmptyDirs();
try { dir.Delete(); }
catch (IOException) {}
catch (UnauthorizedAccessException) {}
}
用途：
static void Main()
{
new DirectoryInfo(@"C:\temp").DeleteEmptyDirs();
}
private static void deleteEmptySubFolders(string ffd, bool deleteIfFileSizeZero=false)
{
DirectoryInfo di = new DirectoryInfo(ffd);
foreach (DirectoryInfo diSon in di.GetDirectories("*", SearchOption.TopDirectoryOnly))
{
FileInfo[] fis = diSon.GetFiles("*.*", SearchOption.AllDirectories);
if (fis == null || fis.Length < 1)
{
diSon.Delete(true);
}
else
{
if (deleteIfFileSizeZero)
{
long total = 0;
foreach (FileInfo fi in fis)
{
total = total + fi.Length;
if (total > 0)
{
break;
}
}
if (total == 0)
{
diSon.Delete(true);
continue;
}
}
deleteEmptySubFolders(diSon.FullName, deleteIfFileSizeZero);
}
}
}
//Recursive scan of empty dirs. See example output bottom
string startDir = @"d:\root";
void Scan(string dir, bool stepBack)
{
//directory not empty
if (Directory.GetFileSystemEntries(dir).Length > 0)
{
if (!stepBack)
{
foreach (string subdir in Directory.GetDirectories(dir))
Scan(subdir, false);
}
}
//directory empty so delete it.
else
{
Directory.Delete(dir);
string prevDir = dir.Substring(0, dir.LastIndexOf("\\"));
if (startDir.Length <= prevDir.Length)
Scan(prevDir, true);
}
}
//call like this
Scan(startDir, false);
/*EXAMPLE outputof d:\root with empty subfolders and one filled with files
Scanning d:\root
Scanning d:\root\folder1 (not empty)
Scanning d:\root\folder1\folder1sub1 (not empty)
Scanning d:\root\folder1\folder1sub1\folder2sub2 (deleted!)
Scanning d:\root\folder1\folder1sub1 (deleted!)
Scanning d:\root\folder1 (deleted)
Scanning d:\root (not empty)
Scanning d:\root\folder2 (not empty)
Scanning d:\root\folder2\folder2sub1 (deleted)
Scanning d:\root\folder2 (not empty)
Scanning d:\root\folder2\notempty (not empty) */
foreach (var folder in Directory.GetDirectories(myDir, "*", System.IO.SearchOption.AllDirectories))
{
{
try
{
if (Directory.GetFiles(folder, "*", System.IO.SearchOption.AllDirectories).Length == 0)
Directory.Delete(folder, true);
}
catch { }
}
}
foreach (var emptyDir in Directory.GetDirectories(root,"*",SearchOption.AllDirectories)
.Select(p=>new DirectoryInfo(p))
.Where(p=>p.GetFiles("*.*", SearchOption.AllDirectories).Count() == 0))
{
emptyDir.Delete();
}