parsing an xml portion (without dom)

My problem is trying to parse an xml portion stored as a string. In trivial case, this is pretty easy by using indexOf() and lastIndexOf() methods, however, when the namespace is dynamic, the problem becomes a little tricky. For instance, when looking for foo, the data may come between

<foo>foo data < /foo> or

<ns1:foo>foo data< /ns1:foo> or

<ns2:foo>foo data< /ns2:foo> and so on..

In my case, i used such a simple solution:

String upToFooPre = fullMessage.substring(0,fullMessage.lastIndexOf("foo&gt ;"));

String upToFoo = upToFooPre.substring(0, upToFooPre.lastIndexOf("&lt ;"));

String foo = upToFoo.substring(upToFoo.lastIndexOf(("&gt ;")) + 4 );