How can I chunk xml to multiple parts in java?

Question

I have a code that creates xml.

public void createXML(InputStream in, String fileName) throws IOException {
    baos = new ByteArrayOutputStream();
    byte[] buf = new byte[BUF_SIZE];
    int readNum = 0;

    Writer writer = new BufferedWriter(new OutputStreamWriter(FileUtil.getOutputStream(fileName, FileUtil.HDD)));
    writer.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n");
    writer.write("\t<" + imageFileName + ">\r\n");
    writer.write("\t\t");

    try {
        while ((readNum = in.read(buf)) >= 0) {
            baos.write(buf, 0, readNum);
            writer.write(baos.toString());
            baos.reset();
        }
    }
    finally {
        if (in != null) {
            in.close();
            baos.close();
        }
    }
    writer.write("\r\n\t<" + imageFileName + ">");
    writer.close();
    baos = null;
    buf = null;
}

I want to create this xml into multiple parts (maximum of 500kb each). How can I do this? Is there any way for me to determine that the created file is already 500kb and write the remaining data to a different file?

I used this but the image after decoding the base64 string, the image produced is corrupted on the portion where it was cut.

for(int i = 1; i <= numberOfFiles; i++){
            baos = new ByteArrayOutputStream();
            String filePartName = fileName + ".part" + i + ".xml";
            Writer writer = new BufferedWriter(new OutputStreamWriter(FileUtil.getOutputStream(filePartName, FileUtil.HDD)));
            writer.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n");
            writer.write("\t<" + filePartName + ">\r\n");
            writer.write("\t\t");

            int size = 0;
            while ((readNum = in.read(buf)) >= 0 && size < 512000) {
                baos.write(buf, 0, readNum);
                size = size + readNum;
                writer.write(baos.toString());
                baos.reset();
            }

            writer.write("\r\n\t<" + filePartName + ">");
            writer.close();
            baos.close();
        }
    }
    in.close();

Answer 1

If you keep a sum total of readNum that is in

while ((readNum = in.read(buf)) >= 0)

then you can test for its value and create new files when ever you want.