How to write unescaped XML to XMLStreamWriter?

Question

I have a number of small XML chunks, that should be embedded in one big XML as child elements. Is there any way to write these chunks to XMLStreamWriter without escaping them?

Answer 1

Below are a couple of options for handling this:

Option #1 - Use javax.xml.transform.Transformer

You could use a javax.xml.transform.Transformer to transform a StreamSource representing your XML fragment onto your StAXResult which is wrapping your XMLStreamWriter.

Option #2 - Interact Directly with the OutputStream

Alternatively you could do something like the following. You can leverage flush() to force the XMLStreamWriter to output its contents. Then you'll note that I do xsw.writeCharacters("") this forces the start element to end for bar before writing the nested XML as a String. The sample code below needs to be flushed out to properly handle encoding issues.

import java.io.*;
import javax.xml.stream.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        OutputStream stream = System.out;
        
        XMLOutputFactory xof = XMLOutputFactory.newFactory();
        XMLStreamWriter xsw = xof.createXMLStreamWriter(stream);
        
        xsw.writeStartDocument();
        xsw.writeStartElement("foo");
        xsw.writeStartElement("bar");
        
        /* Following line is very important, without it unescaped data 
           will appear inside the <bar> tag. */
        xsw.writeCharacters("");
        xsw.flush();
        
        OutputStreamWriter osw = new OutputStreamWriter(stream);
        osw.write("<baz>Hello World<baz>");
        osw.flush();
        
        xsw.writeEndElement();
        xsw.writeEndElement();
        xsw.writeEndDocument();
        xsw.close();
    }

}