如何用Java將目錄中的前20個檔案複製到子目錄中？

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class DirectoryCopier {

    public static void main(String[] args) throws IOException {
        // Get the source directory
        File dir = new File("./source_directory");

        // Create the subdirectory
        String subDirName = "subdirectory";
        File subDir = new File(dir, subDirName);
        boolean success = subDir.mkdir();

        // Iterate over the first 20 files in the directory
        int count = 0;
        for (File review : dir.listFiles()) {
            if (count == 20) {
                break;
            }

            // Copy the file to the subdirectory
            Path sourcePath = Paths.get(review.getAbsolutePath());
            Path targetPath = Paths.get(subDir.getAbsolutePath(), review.getName());
            Files.copy(sourcePath, targetPath);

            count++;
        }
    }
}