Downloading Zip File through HttpResponse Java

Question

So I'm grabbing a collection of blobs from a database (various mimetypes) and trying to zip them up to be downloaded by users through an http response. I can get the download to happen, but when I try to open the downloaded zip file it says "The archive is either in unknown format or damaged." I've tried the following code with application/zip, application/octet-stream, and application/x-zip-compressed, but I'm starting to assume that the issue is in how I'm adding the files. I'm also using Java 7 and Grails 2.2.4.

Any help with this would be greatly appreciated. Thanks!

  final ZipOutputStream out = new ZipOutputStream(new FileOutputStream("test.zip"));


        for (Long id : ids){

            Object[] stream = inlineSamplesDataProvider.getAttachmentStream(id);


            if (stream) {

                String fileName = stream[0]
                String mimeType = (String) stream[1];
                InputStream inputStream = stream[2]
                byte[] byteStream = inputStream.getBytes();

                ZipEntry zipEntry = new ZipEntry(fileName)
                out.putNextEntry(zipEntry);
                out.write(byteStream, 0, byteStream.length);
                out.closeEntry();
            }
        }

        out.close();
        response.setHeader("Content-Disposition", "attachment; filename=\"" + "test.zip" + "\"");
        response.setHeader("Content-Type", "application/zip");
        response.outputStream << out;
        response.outputstream.flush();

Answer 1

I found the answer here: Returning ZipOutputStream to browser

All right, so what ended up working for me was converting the ZipOutputStream to a ByteArrayOutputStream and writing it to a response as a byte[]:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
final ZipOutputStream out = new ZipOutputStream(baos);

Calendar cal = Calendar.getInstance();
String date = new SimpleDateFormat("MMM-dd").format(cal.getTime());

final String zipName = "COA_Images-" + date + ".zip";

for (Long id: ids) {

    Object[] stream = inlineSamplesDataProvider.getAttachmentStream(id);

    if (stream) {

        String fileName = stream[0];
        String mimeType = (String) stream[1];
        InputStream inputStream = stream[2];
        byte[] byteStream = inputStream.getBytes();

        ZipEntry zipEntry = new ZipEntry(fileName)
        out.putNextEntry(zipEntry);
        out.write(byteStream, 0, byteStream.length);
        out.closeEntry();
    }
}

out.close();

response.setHeader("Content-Disposition", "attachment; filename=\"" + zipName + "\"");
response.setHeader("Content-Type", "application/zip");
response.getOutputStream().write(baos.toByteArray());
response.flushBuffer();
baos.close();

Thanks to everyone who helped!