In this article, you'll learn how to copy all files and sub-directories from one directory to another directory using Java NIO API as well as Apache Commons IO.

Using Files.copy() Method

In Java 8 and higher, you can use Files.copy() combined with Files.walk() from NIO API to copy all files and sub-directories from one director to another in Java:

try {
    // source & destination directories
    Path src = Paths.get("dir");
    Path dest = Paths.get("dir-new");

    // create stream for `src`
    Stream<Path> files = Files.walk(src);

    // copy all files and folders from `src` to `dest`
    files.forEach(file -> {
        try {
            Files.copy(file, dest.resolve(src.relativize(file)),
                    StandardCopyOption.REPLACE_EXISTING);
        } catch (IOException e) {
            e.printStackTrace();
        }
    });

    // close the stream
    files.close();

} catch (IOException ex) {
    ex.printStackTrace();
}

Using Apache Commons IO

The Apache Commons IO library provides FileUtils.copyDirectory() method to copy all files and sub-directories from one directory to another directory. Here is an example:

try {
    // source & destination directories
    File src = new File("dir");
    File dest = new File("dir-new");

    // copy all files and folders from `src` to `dest`
    FileUtils.copyDirectory(src, dest);
        
} catch (IOException ex) {
    ex.printStackTrace();
}

Don't forget to include Apache Commons IO dependency to your Maven's project pom.xml file:

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.6</version>
</dependency>

For a Gradle project, add the following dependency to your build.gralde file:

implementation 'commons-io:commons-io:2.6'

Further Reading

You may be interested in other Java I/O articles:

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