java.nio.file.Files.delete(路径)-偶尔无法使用SimpleFileVisitor递归删除目录 [英] java.nio.file.Files.delete(Path path) - occasional failure to recursively delete directory using SimpleFileVisitor
问题描述
尝试使用从用Java递归删除目录
代码(归功于@TrevorRobinson):
Code (credit to @TrevorRobinson) :
static void removeRecursive(Path path) throws IOException {
Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
final Logger logger = LoggerFactory.getLogger(this.getClass());
@Override
public FileVisitResult visitFile(Path file,
BasicFileAttributes attrs) throws IOException {
logger.warn("Deleting " + file.getFileName());
Files.delete(file);
logger.warn("DELETED " + file.getFileName());
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFileFailed(Path file, IOException exc) {
// try to delete the file anyway, even if its attributes could
// not be read, since delete-only access is theoretically possible
// I NEVER SEE THIS
logger.warn("Delete file " + file + " failed", exc);
try {
Files.delete(file);
} catch (IOException e) {
logger.warn(
"Delete file " + file + " failed again", exc);
}
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult postVisitDirectory(Path dir, IOException exc)
throws IOException {
if (exc == null) {
Files.delete(dir);
return FileVisitResult.CONTINUE;
}
// directory iteration failed; propagate exception
throw exc;
}
});
}
致电:
try {
removeRecursive(Paths.get(unzipDirPath));
} catch (IOException e) {
String msg = "Failed to delete folder " + unzipDirPath;
if (e instanceof java.nio.file.DirectoryNotEmptyException) {
msg += ". Still contains : ";
final File[] listFiles = Paths.get(unzipDirPath).toFile().listFiles();
if (listFiles != null) for (File file : listFiles) {
msg += file.getAbsolutePath() + "\n";
}
}
log.error(msg, e);
}
打印(一次重复20/40次):
Prints (once in 20/40 iterations):
22:03:34.190 [http-bio-8080-exec-47] WARN g.u.d.m.server.servlets.Controller$1 - Deleting batt
22:03:34.192 [http-bio-8080-exec-47] WARN g.u.d.m.server.servlets.Controller$1 - DELETED batt
22:03:34.192 [http-bio-8080-exec-47] WARN g.u.d.m.server.servlets.Controller$1 - Deleting wifi
22:03:34.193 [http-bio-8080-exec-47] WARN g.u.d.m.server.servlets.Controller$1 - DELETED wifi
22:03:34.196 [http-bio-8080-exec-47] ERROR g.u.d.m.s.s.DataCollectionServlet - Failed to delete folder C:\yada\. Still contains : C:\yada\dir\wifi
java.nio.file.DirectoryNotEmptyException: C:\yada\dir
at sun.nio.fs.WindowsFileSystemProvider.implDelete(WindowsFileSystemProvider.java:265) ~[na:1.7.0_45]
at sun.nio.fs.AbstractFileSystemProvider.delete(AbstractFileSystemProvider.java:103) ~[na:1.7.0_45]
at java.nio.file.Files.delete(Files.java:1077) ~[na:1.7.0_45]
at gr.uoa.di.monitoring.server.servlets.Controller$1.postVisitDirectory(Controller.java:128) ~[Controller$1.class:na]
at gr.uoa.di.monitoring.server.servlets.Controller$1.postVisitDirectory(Controller.java:1) ~[Controller$1.class:na]
at java.nio.file.FileTreeWalker.walk(FileTreeWalker.java:224) ~[na:1.7.0_45]
at java.nio.file.FileTreeWalker.walk(FileTreeWalker.java:199) ~[na:1.7.0_45]
at java.nio.file.FileTreeWalker.walk(FileTreeWalker.java:69) ~[na:1.7.0_45]
at java.nio.file.Files.walkFileTree(Files.java:2600) ~[na:1.7.0_45]
at java.nio.file.Files.walkFileTree(Files.java:2633) ~[na:1.7.0_45]
at gr.uoa.di.monitoring.server.servlets.Controller.removeRecursive(Controller.java:96) ~[Controller.class:na]
at gr.uoa.di.monitoring.server.servlets.DataCollectionServlet.doPost(DataCollectionServlet.java:153) ~[DataCollectionServlet.class:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641) [servlet-api.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) [servlet-api.jar:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) [catalina.jar:7.0.32]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.32]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) [catalina.jar:7.0.32]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) [catalina.jar:7.0.32]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) [catalina.jar:7.0.32]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) [catalina.jar:7.0.32]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) [catalina.jar:7.0.32]
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929) [catalina.jar:7.0.32]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) [catalina.jar:7.0.32]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) [catalina.jar:7.0.32]
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002) [tomcat-coyote.jar:7.0.32]
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585) [tomcat-coyote.jar:7.0.32]
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310) [tomcat-coyote.jar:7.0.32]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_45]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_45]
at java.lang.Thread.run(Thread.java:744) [na:1.7.0_45]
请注意，wifi被报告为已删除-更奇怪的是，有时我会得到:
Notice that wifi is reported as deleted - what's even more weird is that sometimes I get :
无法删除文件夹C:\ yada.仍包含:C:\ yada \ dir
Failed to delete folder C:\yada. Still contains : C:\yada\dir
java.nio.file.DirectoryNotEmptyException:C:\ yada \ dir
java.nio.file.DirectoryNotEmptyException: C:\yada\dir
我倾向于得出这样的结论，即删除有时会花费太长时间-换句话说，问题是java.nio.file.Files.delete(Path path)不会阻塞(因此C:\ yada \ dir在时间到了时仍包含文件，有时会被删除.我统计的时间).那么我该如何解决呢?
I tend towards the conclusion that occasionally the deletion takes too long - in other words the problem is that java.nio.file.Files.delete(Path path) does not block (so C:\yada\dir still contains files when its time comes, which sometimes are deleted by the time I stat it). So how am I to workaround this ?
也:java.nio.file.Files.delete(Path path)是否需要抛出?
Also : is java.nio.file.Files.delete(Path path) required to throw ? The docs state :
在某些操作系统上，当此Java虚拟机或其他程序打开并使用文件时，可能无法删除该文件.
On some operating systems it may not be possible to remove a file when it is open and in use by this Java virtual machine or other programs.
在这种情况下，似乎不需要引发异常. java.nio.file.Files.delete(Path path)是否需要抛出?
Does not seem to require an exception to be thrown in this case. Is java.nio.file.Files.delete(Path path) required to throw ?
推荐答案
我遇到了相同的问题，结果发现该问题是由于我正在删除内容的同一目录的代码中其他地方的未关闭目录文件流引起的从.流对象返回:
I was having the same problem and it turned out the problem was caused by an unclosed directory file stream somewhere else in the code for the same directory I was deleting stuff from. The stream object returned by:
Files.list(Path)
必须关闭，因此如果使用该方法，请确保在代码中使用try-with-resources构造.
must be closed, so be sure to use the try-with-resources construct in your code if using that method.
因此，我认为删除的时间不会太长，我尝试了一次尝试，然后重新尝试删除目录，但没有任何运气.您自己的程序很可能已锁定该资源.结果是，尽管它成功返回，但对它的delete调用仍未完成(看起来Windows最终将在您自己的程序释放该文件后删除该文件)，但是当然不能删除包含目录，因为该目录确实尚未删除空的.
So I don't think it's that the deletion takes too long, I tried a wait before re-attempting directory deletion without any luck. It's most likely that your own program has that resource locked. The result is that the delete call on it doesn't complete although it returns successfully (it looks like Windows will eventually delete the file once your own program frees it) but then of course the containing directory cannot be deleted as that is indeed not yet empty.
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