Files.walkFileTree methods to visit each file in
a file tree.
Usage Examples: Suppose we want to delete a file tree. In that case, each directory should be deleted after the entries in the directory are deleted.
Path start = ... Files.walkFileTree(start, new SimpleFileVisitor<Path>() { @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { Files.delete(file); return FileVisitResult.CONTINUE; } @Override public FileVisitResult postVisitDirectory(Path dir, IOException e) throws IOException { if (e == null) { Files.delete(dir); return FileVisitResult.CONTINUE; } else { // directory iteration failed throw e; } } });
Furthermore, suppose we want to copy a file tree to a target location. In that case, symbolic links should be followed and the target directory should be created before the entries in the directory are copied.
final Path source = ... final Path target = ... Files.walkFileTree(source, EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE, new SimpleFileVisitor<Path>() { @Override public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException { Path targetdir = target.resolve(source.relativize(dir)); try { Files.copy(dir, targetdir); } catch (FileAlreadyExistsException e) { if (!Files.isDirectory(targetdir)) throw e; } return CONTINUE; } @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { Files.copy(file, target.resolve(source.relativize(file))); return CONTINUE; } });
| Modifier and Type | Method and Description |
|---|---|
| public FileVisitResult | Returns: the visit resulta reference to the directory dir, IOException null if the iteration of the directory completes without
an error; otherwise the I/O exception that caused the iteration
of the directory to complete prematurelyInvoked for a directory after entries in the directory, and all of their descendants, have been visited. |
| public FileVisitResult | Returns: the visit resulta reference to the directory dir, BasicFileAttributes the directory's basic attributes attrs)Invoked for a directory before entries in the directory are visited. |
| public FileVisitResult | Returns: the visit resulta reference to the file file, BasicFileAttributes the file's basic attributes attrs)Invoked for a file in a directory. |
| public FileVisitResult | Returns: the visit resulta reference to the file file, IOException the I/O exception that prevented the file from being visited exc)Invoked for a file that could not be visited. |
| postVisitDirectory | back to summary |
|---|---|
| public FileVisitResult postVisitDirectory(T dir, IOException exc) throws IOException Invoked for a directory after entries in the directory, and all of their
descendants, have been visited. This method is also invoked when iteration
of the directory completes prematurely (by a
| |
| preVisitDirectory | back to summary |
|---|---|
| public FileVisitResult preVisitDirectory(T dir, BasicFileAttributes attrs) throws IOException Invoked for a directory before entries in the directory are visited. If this method returns
| |
| visitFile | back to summary |
|---|---|
| public FileVisitResult visitFile(T file, BasicFileAttributes attrs) throws IOException Invoked for a file in a directory.
| |
| visitFileFailed | back to summary |
|---|---|
| public FileVisitResult visitFileFailed(T file, IOException exc) throws IOException Invoked for a file that could not be visited. This method is invoked if the file's attributes could not be read, the file is a directory that could not be opened, and other reasons.
| |