java tar和gzip目录，但最终结果不是.tar.gz格式，结果只是一个常规文件

import java.io.*;
import org.apache.commons.compress.archivers.tar.*;
import org.apache.commons.compress.compressors.gzip.*;

public class TarGzipCompressor {
    public static void main(String[] args) {
        String sourceDir = "path/to/source/directory";
        String outputFileName = "output.tar.gz";

        try {
            File source = new File(sourceDir);
            FileOutputStream fos = new FileOutputStream(outputFileName);
            BufferedOutputStream bos = new BufferedOutputStream(fos);
            GzipCompressorOutputStream gzos = new GzipCompressorOutputStream(bos);
            TarArchiveOutputStream tarOS = new TarArchiveOutputStream(gzos);

            addFilesToTarGZ(source, "", tarOS);

            tarOS.finish();
            tarOS.close();
            gzos.close();
            bos.close();
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void addFilesToTarGZ(File file, String parentPath, TarArchiveOutputStream tarOS) throws IOException {
        String entryName = parentPath + file.getName();
        TarArchiveEntry tarEntry = new TarArchiveEntry(file, entryName);
        tarOS.putArchiveEntry(tarEntry);

        if (file.isFile()) {
            try (FileInputStream fis = new FileInputStream(file)) {
                byte[] buffer = new byte[1024];
                int len;
                while ((len = fis.read(buffer)) != -1) {
                    tarOS.write(buffer, 0, len);
                }
            }
            tarOS.closeArchiveEntry();
        } else if (file.isDirectory()) {
            tarOS.closeArchiveEntry();
            File[] children = file.listFiles();
            if (children != null) {
                for (File child : children) {
                    addFilesToTarGZ(child, entryName + "/", tarOS);
                }
            }
        }
    }
}