Java 8: Copy directory recursively?

Question

I see that Java 8 has significantly cleaned up reading the contents of a file into a String:

String contents = new String(Files.readAllBytes(Paths.get(new URI(so         


        

Answer 1

Using Files.walkFileTree:

• you don't need to worry about closing Streams.
  (some other answers here forget that while using Files.walk)
• handles IOException elegantly.
  (Some other answers here would become more difficult when adding proper exception handling instead of a simple printStackTrace)

    public void copyFolder(Path source, Path target, CopyOption... options)
            throws IOException {
        Files.walkFileTree(source, new SimpleFileVisitor() {

            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
                    throws IOException {
                createDirectories(target.resolve(source.relativize(dir)));
                return FileVisitResult.CONTINUE;
            }

            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
                    throws IOException {
                copy(file, target.resolve(source.relativize(file)), options);
                return FileVisitResult.CONTINUE;
            }
        });
    }

What this does is

• walk recursively over all files in the directory.
• When a directory is encountered (preVisitDirectory):
  create the corresponding one in the target directory.
• When a regular file is encountered (visitFile):
  copy it.

options can be used to tailor the copy to your needs. For example to overwrite existing files in the target directory, use copyFolder(source, target, StandardCopyOption.REPLACE_EXISTING);