Jaxb - Marshall - How can I format the xml attributes - For example, putting a line break after each attribute

Question

I'm trying to find a way to format the xml so that each attribute will be in a new line.

code :

        OutputFormat of = new OutputFormat();
        of.setIndent(4);
        XMLSerializer serializer = new XMLSerializer(of);
        Writer stringWriter = new StringWriter();
        serializer.setOutputCharStream(stringWriter);

        marshaller.marshal(target, serializer.asContentHandler());
        results = stringWriter.toString();

I'm trying to get this:

<blablabla isGood="false" newInstance="false" id="cse_a"
    deleted="false" name="cse_a"
    xmlns:blabla="http://www.blabla.com">

    <Description><![CDATA[]]></Description>
    <Name><![CDATA[A]]></Name>

</blablabla>

To look like this:

<blablabla isGood="false"
           newInstance="false"
           id="cse_a"
           deleted="false"
           name="cse_a"
           xmlns:blabla="http://www.blabla.com">

    <Description><![CDATA[]]></Description>
    <DisplayName><![CDATA[A]]></DisplayName>

</blablabla>

thanks!

Answer 1

Just an example of Blaise Doughan answer, with ContentHandler:

import java.io.IOException;
import java.io.Writer;

import org.apache.commons.lang3.StringUtils;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class WriteOutContentHandler extends DefaultHandler
{

    private static final String NEWLINE = System.getProperty("line.separator");
    private static final String INDENT = "  ";

    private Writer _writer;
    private int depth = 0;

    public WriteOutContentHandler(Writer writer)
    {
        _writer = writer;
    }

    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException
    {
        try
        {
            _writer.write(ch, start, length);
        } catch (IOException e)
        {
            throw new SAXException("Error writing out character content", e);
        }
    }

    @Override
    public void ignorableWhitespace(char[] ch, int start, int length)
            throws SAXException
    {
        try
        {
            _writer.write(ch, start, length);
        } catch (IOException e)
        {
            throw new SAXException("Error writing out character content", e);
        }
    }

    @Override
    public void endDocument() throws SAXException
    {
        try
        {
            _writer.flush();
        } catch (IOException e)
        {
            throw new SAXException("Error flushing character output", e);
        }
    }

    @Override
    public String toString()
    {
        return _writer.toString();
    }

    @Override
    public void startElement(String uri, String localName, String qName,
            Attributes attrs) throws SAXException
    {
        write(NEWLINE);
        write(StringUtils.repeat(INDENT, depth));
        depth++;

        String eName = localName;

        if ("".equals(eName))
        {
            eName = qName;
        }

        write("<" + eName);

        if (attrs != null)
        {
            for (int i = 0; i < attrs.getLength(); i++)
            {
                String attrName = attrs.getLocalName(i);

                if ("".equals(attrName))
                {
                    attrName = attrs.getQName(i);
                }

                write(NEWLINE);
                write(StringUtils.repeat(INDENT, depth));
                write(attrName);

                write("=\"");
                write(attrs.getValue(i));
                write("\"");
            }
        }

        if (attrs.getLength() > 0)
        {
            write(NEWLINE);
            write(StringUtils.repeat(INDENT, depth-1));
        }

        write(">");
    }

    @Override
    public void endElement(String namespaceURI, String sName, String qName) throws SAXException
    {
        write(NEWLINE);
        depth--;
        write(StringUtils.repeat(INDENT, depth));

        String eName = sName;
        if ("".equals(eName))
        {
            eName = qName;
        }
        write("</" + eName + ">");
    }

    private void write(String s) throws SAXException
    {
        try
        {
            _writer.write(s);
            _writer.flush();
        } catch (IOException e)
        {
            throw new SAXException("I/O error", e);
        }
    }
}

And usage:

    StringWriter writer = new StringWriter();
    JAXBContext jc = JAXBContext.newInstance(MODEL);
    Marshaller marshaller = jc.createMarshaller();
    marshaller.marshal(node, new WriteOutContentHandler(writer));

    return writer.toString();