Question

I was parsing an XML that has an image that is Base64 encoded. I would like to extract the image and parse the remainder of the XML. The code I have written to extract the image is as below:

private void saveFormImage(String imageText) throws IOException {
    FileOutputStream  fos = null;
    try {
        Base64 base64=new Base64();
        byte decoded[]=base64.decode(imageText.getBytes());
        File file = new File(<file loc>);
        fos = new FileOutputStream(file);
        fos.write(decoded);
    } finally {
        IOUtils.closeQuietly(fos);
    }
}

I use JDOM to parse the XML and obtain the imageText first as a String and pass the string to this method. I then use the Apache codec library to decode the Base64 encoded data and store into a file.

Is this the best way to do this? This is not awfully fast. It finishes in about 2s. Is there a faster and memory efficient way of doing this?

As updated in a comment below – Is there a way to pipe the data from the XML directly onto an OutputStream and just decoding a buffer in memory? Is this a more memory efficient way of doing things? Or should this matter when the XML size would be max 2.5 MB.

Answer 1

What about the rest of the XML of the document? Do you want discard it?

If yes, then have a look at STAX (Streaming API for XML):

http://docs.oracle.com/javase/7/docs/api/javax/xml/stream/package-summary.html

It’s part of Java SE 6.

If you want to parse the rest of the document as well, consider JAXB with custom bindings.