java.nio.file.Files.delete(Path path) - 偶尔使用SimpleFileVisitor以递归方式删除目录失败

Question

尝试在Java中java.nio.file.DirectoryNotEmptyException递归删除从Delete目录中删除的递归删除方法中的偶然问题

代码(归功于@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(一次在20/40次迭代中):

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报告为已删除 - 更奇怪的是,有时我会得到:

无法删除文件夹C:\ yada.仍然包含:C:\ yada\dir

java.nio.file.DirectoryNotEmptyException:C:\ yada\dir

我倾向于得出结论,偶尔删除时间太长 - 换句话说,问题是java.nio.file.Files.delete(Path path)不会阻塞(因此C:\ yada\dir在时间到来时仍然包含文件,有时在我统计时删除) .那么我该如何解决这个问题呢？

另外:java.nio.file.Files.delete(Path path)需要扔？该文档的状态:

在某些操作系统上,可能无法在文件被Java虚拟机或其他程序打开和使用时删除该文件.

在这种情况下似乎不需要抛出异常.是否java.nio.file.Files.delete(Path path)需要抛出？

Answer 1

我遇到了同样的问题,事实证明问题是由一个未封闭的目录文件流引起的,我在同一个目录的代码中的某个地方删除了东西.返回的流对象:

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.

所以我不认为删除时间太长,我尝试等待重新尝试删除目录而没有任何运气.您自己的程序很可能已锁定该资源.结果是它的删除调用虽然成功返回但没有完成(看起来Windows会在你自己的程序释放后最终删除文件),但当然包含的目录不能删除,因为它确实还没有空.

Answer 2

您可以将当前正在迭代的文件的名称临时存储在变量中，并在DirectoryNotEmptyException. 当发生此异常时，捕获它并抛出您自己的指定文件的异常。

try {
 Files.delete(file);
} catch (DirectoryNotEmptyException  e) {
 throw new MySpecificException(file.getFileName());
}

class MySpecificException extends Exception {
 public MySpecificException() { }

 public MySpecificException(string filename) {
  super(filename);
 }  
}

获取文件名可以通过e.getMessage();

我假设Files.delete()当遇到无法删除的文件时继续删除目录中的文件。如果是这种情况，我的方法仍然有效：只需返回目录中所有文件的列表，而不是目录的文件名。它应该只包含无法删除的文件，并且您仍然拥有解决方案。