How do I write XML files directly to a zip archive?

Question

What is the proper way to write a list of XML files using JAXB directly to a zip archive without using a 3rd party library.

Would it be better to just write all the XML files to a directory and then zip?

Answer 1

As others pointed out, you can use the ZipOutputStream class to create a ZIP-file. The trick to put multiple files in a single ZIP-file is to use the ZipEntry descriptors prior to writing (marshalling) the JAXB XML data in the ZipOutputStream. So your code might look similar to this one:

JAXBElement jaxbElement1 = objectFactory.createRoot(rootType);
JAXBElement jaxbElement2 = objectFactory.createRoot(rootType);

ZipOutputStream zos = null; 
try {
  zos = new ZipOutputStream(new FileOutputStream("xml-file.zip"));
  // add zip-entry descriptor
  ZipEntry ze1 = new ZipEntry("xml-file-1.xml");
  zos.putNextEntry(ze1);
  // add zip-entry data
  marshaller.marshal(jaxbElement1, zos);
  ZipEntry ze2 = new ZipEntry("xml-file-2.xml");
  zos.putNextEntry(ze2);
  marshaller.marshal(jaxbElement2, zos);
  zos.flush();
} finally {
  if (zos != null) {
    zos.close();
  }
}