Copying files from one directory to another in Java

Question

For now this should solve your problem

File source = new File("H:\\work-temp\\file");
File dest = new File("H:\\work-temp\\file2");
try {
    FileUtils.copyDirectory(source, dest);
} catch (IOException e) {
    e.printStackTrace();
}

FileUtils class from apache commons-io library, available since version 1.2.

Using third party tools instead of writing all utilities by ourself seems to be a better idea. It can save time and other valuable resources.

There is no file copy method in the Standard API (yet). Your options are:

• Write it yourself, using a FileInputStream, a FileOutputStream and a buffer to copy bytes from one to the other - or better yet, use FileChannel.transferTo()
• User Apache Commons' FileUtils
• Wait for NIO2 in Java 7

In Java 7, there is a standard method to copy files in java:

Files.copy.

It integrates with O/S native I/O for high performance.

See my A on Standard concise way to copy a file in Java? for a full description of usage.

The example below from Java Tips is rather straight forward. I have since switched to Groovy for operations dealing with the file system - much easier and elegant. But here is the Java Tips one I used in the past. It lacks the robust exception handling that is required to make it fool-proof.

 public void copyDirectory(File sourceLocation , File targetLocation)
    throws IOException {

        if (sourceLocation.isDirectory()) {
            if (!targetLocation.exists()) {
                targetLocation.mkdir();
            }

            String[] children = sourceLocation.list();
            for (int i=0; i<children.length; i++) {
                copyDirectory(new File(sourceLocation, children[i]),
                        new File(targetLocation, children[i]));
            }
        } else {

            InputStream in = new FileInputStream(sourceLocation);
            OutputStream out = new FileOutputStream(targetLocation);

            // Copy the bits from instream to outstream
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
            in.close();
            out.close();
        }
    }

If you want to copy a file and not move it you can code like this.

private static void copyFile(File sourceFile, File destFile)
        throws IOException {
    if (!sourceFile.exists()) {
        return;
    }
    if (!destFile.exists()) {
        destFile.createNewFile();
    }
    FileChannel source = null;
    FileChannel destination = null;
    source = new FileInputStream(sourceFile).getChannel();
    destination = new FileOutputStream(destFile).getChannel();
    if (destination != null && source != null) {
        destination.transferFrom(source, 0, source.size());
    }
    if (source != null) {
        source.close();
    }
    if (destination != null) {
        destination.close();
    }

}

Spring Framework has many similar util classes like Apache Commons Lang. So there is org.springframework.util.FileSystemUtils

File src = new File("/home/user/src");
File dest = new File("/home/user/dest");
FileSystemUtils.copyRecursively(src, dest);

apache commons Fileutils is handy. you can do below activities.

1. copying file from one directory to another directory.

   use copyFileToDirectory(File srcFile, File destDir)

2. copying directory from one directory to another directory.

   use copyDirectory(File srcDir, File destDir)

3. copying contents of one file to another

   use static void copyFile(File srcFile, File destFile)