如何将输入流传输到压缩文件,因为它是用Java读入的？

import java.io.*;
import java.util.zip.GZIPOutputStream;

public class InputStreamToGzip {
    public static void main(String[] args) throws IOException {
        InputStream inputStream = new FileInputStream("input.txt");
        OutputStream outputStream = new GZIPOutputStream(new FileOutputStream("input.txt.gz"));

        byte[] buffer = new byte[1024];
        int bytesRead;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }

        inputStream.close();
        outputStream.close();
    }
}