How to copy a folder and all its subfolders and files into another folder [duplicate]

Question

How can I copy a folder and all its subfolders and files into another folder?

Answer 1

Choose what you like:

• FileUtils from Apache Commons IO (the easiest and safest way)

Example with FileUtils:

File srcDir = new File("C:/Demo/source");
File destDir = new File("C:/Demo/target");
FileUtils.copyDirectory(srcDir, destDir);

• Manually, example before Java 7 (CHANGE: close streams in the finally-block)
• Manually, Java >=7

Example with AutoCloseable feature in Java 7:

public void copy(File sourceLocation, File targetLocation) throws IOException {
    if (sourceLocation.isDirectory()) {
        copyDirectory(sourceLocation, targetLocation);
    } else {
        copyFile(sourceLocation, targetLocation);
    }
}

private void copyDirectory(File source, File target) throws IOException {
    if (!target.exists()) {
        target.mkdir();
    }

    for (String f : source.list()) {
        copy(new File(source, f), new File(target, f));
    }
}

private void copyFile(File source, File target) throws IOException {        
    try (
            InputStream in = new FileInputStream(source);
            OutputStream out = new FileOutputStream(target)
    ) {
        byte[] buf = new byte[1024];
        int length;
        while ((length = in.read(buf)) > 0) {
            out.write(buf, 0, length);
        }
    }
}