java - Getting all content of a xml node as string

I am using this code to parsing xml

    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();
    InputSource is = new InputSource();
    is.setCharacterStream(new StringReader(data));
    Document doc = db.parse(is);

Now I want to get all content from a xml node. Like from this xml

<?xml version='1.0'?>
<type>
  <human>                     
    <Name>John Smith</Name>              
    <Address>1/3A South Garden</Address>    
  </human>
</type>

So if want to get all content of <human> as text.

<Name>John Smith</Name>
<Address>1/3A South Garden</Address>

How can I get it ?