java - ユーザーファイルシステムを読み取るAccessDeniedException

Question

currentUserPath（デフォルトではSystem.getProperty("user.home")で初期化）のファイル名を含むJavaFX ListViewで使用されるOberservableListを返すことになっているこのメソッドがあります。

public ObservableList<String> getUserItems(){ 
     ObservableList<String> fileList = FXCollections.observableArrayList(); 
     try { 
      Files.walk(Paths.get(currentUserPath)).forEach(filePath -> { 
        if (Files.isRegularFile(filePath)) { 
         fileList.add(filePath.getFileName().toString()); 
        } 
       }); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     return fileList; 

    } 

残念ながら、このメソッドを呼び出すと、AccessDeniedExceptionが返されます。スタックトレースは次のとおりです。

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException 
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774) 
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657) 
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49) 
    at javafx.event.Event.fireEvent(Event.java:198) 
    at javafx.scene.Node.fireEvent(Node.java:8411) 
    at javafx.scene.control.Button.fire(Button.java:185) 
    at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182) 
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96) 
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89) 
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218) 
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54) 
    at javafx.event.Event.fireEvent(Event.java:198) 
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3757) 
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485) 
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762) 
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:380) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416) 
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389) 
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415) 
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555) 
    at com.sun.glass.ui.View.notifyMouse(View.java:937) 
    at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method) 
    at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139) 
    at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.reflect.InvocationTargetException 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:498) 
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:498) 
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769) 
    ... 48 more 
Caused by: java.io.UncheckedIOException: java.nio.file.AccessDeniedException: /home/adam/.gconf/apps/gedit-2 
    at java.nio.file.FileTreeIterator.fetchNextIfNeeded(FileTreeIterator.java:88) 
    at java.nio.file.FileTreeIterator.hasNext(FileTreeIterator.java:104) 
    at java.util.Iterator.forEachRemaining(Iterator.java:115) 
    at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801) 
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) 
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) 
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151) 
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174) 
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) 
    at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418) 
    at application.FTPDownload.getUserItems(FTPDownload.java:147) 
    at application.FTPController.handleConnectButtonAction(FTPController.java:23) 
    ... 58 more 
Caused by: java.nio.file.AccessDeniedException: /home/adam/.gconf/apps/gedit-2 
    at sun.nio.fs.UnixException.translateToIOException(UnixException.java:84) 
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102) 
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107) 
    at sun.nio.fs.UnixFileSystemProvider.newDirectoryStream(UnixFileSystemProvider.java:427) 
    at java.nio.file.Files.newDirectoryStream(Files.java:457) 
    at java.nio.file.FileTreeWalker.visit(FileTreeWalker.java:300) 
    at java.nio.file.FileTreeWalker.next(FileTreeWalker.java:372) 
    at java.nio.file.FileTreeIterator.fetchNextIfNeeded(FileTreeIterator.java:84) 
    ... 69 more 

誰でもこの例外が発生する理由を教えてください。どんな助けでも大歓迎です。

Answer 1

その例外のjavadocは言う：

「[これは]は、ファイルシステム操作が拒否されたときに、ファイルのアクセス許可またはその他のアクセスチェックのために、通常、スロー[つまり]例外を確認しました。」

ほとんどの場合、アプリケーションが実行されているアカウントに「/home/adam/.gconf/apps/gedit-2」ディレクトリを読み取る権限がありません。

Answer 2

これは、実行中のプログラムが指定されたファイルにアクセスできないためです。スタックトレースから ：

Caused by: java.io.UncheckedIOException: java.nio.file.AccessDeniedException: /home/adam/.gconf/apps/gedit-2 
Caused by: java.nio.file.AccessDeniedException: /home/adam/.gconf/apps/gedit-2 

は、それがプログラムを実行しているユーザがアクセス可能かどうか、/homeディレクトリと/home/adam/.gconf/apps/gedit-2ファイルのパーミッションを参照してください。

他の可能性として、そのようなファイル/ディレクトリはありません。