Writing XML files

Question

Hello all
There's a vast amount of information on the java.sun.com site about parsing XML files:
* creating DOM trees in memory from an XML file
* setting up event handlers to be called when an XML file is parsed
* transforming XML files using XSL.
However, I can find very little information anywhere about writing XML files in the first place! I'm already aware of two ways to do this:
(1) create a DOM in memory and write this to a file. If the data is large, though, this isn't feasible.
(2) just output the XML elements directly to some file as text. This doesn't take account of the encoding, or special characters, and the document is not necessarily then syntactically valid.
Is there some API which I haven't yet come across that is designed specifically for writing XML data to files? If it's built in to Java 2, then goodness knows how I've missed it all this time; if it's third-party, I'd be grateful for any links.
Thanks for your help
Rich Fearn

Answer 1

I know pastes can be horrible, but this is a working example which I find useful: SAX XML output ;)
import java.io.*;
// SAX classes.
import org.xml.sax.*;
import org.xml.sax.helpers.*;
//JAXP 1.1
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
import javax.xml.transform.sax.*;
                //AlphabetXMLOut(file, alphabets);
class AlphabetXMLOut {
        public void run(){
                try{
                        FileOutputStream fos = new FileOutputStream("output.xml");
                        PrintWriter out = new PrintWriter(fos);
                        StreamResult streamResult = new StreamResult(out);
                        // PrintWriter from a Servlet
                        //PrintWriter out = response.getWriter();
                        //StreamResult streamResult = new StreamResult(out);
                        SAXTransformerFactory tf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
                        // SAX2.0 ContentHandler.
                        TransformerHandler hd = tf.newTransformerHandler();
                        Transformer serializer = hd.getTransformer();
                        serializer.setOutputProperty(OutputKeys.ENCODING,"ISO-8859-1");
                        serializer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM,"users.dtd");
                        serializer.setOutputProperty(OutputKeys.INDENT,"yes");
                        hd.setResult(streamResult);
                        hd.startDocument();
                        AttributesImpl atts = new AttributesImpl();
                        // USERS tag.
                        hd.startElement("","","USERS",atts);
                        // USER tags.
                        String[] id = {"PWD122","MX787","A4Q45"};
                        String[] type = {"customer","manager","employee"};
                        String[] desc = {"Tim@Home","Jack&Moud","John D'oe"};
                        for (int i=0;i<id.length;i++){
                                atts.clear();
                                atts.addAttribute("","","ID","CDATA",id);
atts.addAttribute("","","TYPE","CDATA",type[i]);
hd.startElement("","","USER",atts);
hd.characters(desc[i].toCharArray(),0,desc[i].length());
hd.endElement("","","USER");
hd.endElement("","","USERS");
hd.endDocument();
fos.close();
}catch (IOException e){
System.err.println ("Unable to write to file");
System.exit(-1);
}catch (TransformerConfigurationException tce){
System.err.println("Error in: TransformerConfigurationException");
}catch (SAXException spe) {
// Error generated by the parser
System.err.println("Error in: (SAXException");
// Use the contained exception, if any
Exception x = spe;
if (spe.getException() != null)
x = spe.getException();
x.printStackTrace();
-Hope this helps