<?xml version="1.0" encoding="WINDOWS-1251"?>
<file>
</file>

<?xml version="1.0" encoding="WINDOWS-1251"?>
    <file>
       <record>
          ...
       </record>
    </file>

def xml
        try {
            xml = new XmlParser().parse(file)
        } catch (IOException e) {
        }
        record = XmlUtil.serialize(record)
        xml.appendNode(record)
        def a = XmlUtil.serialize(xml)

file[attributes={}; value=[<record index="1">
</record>
[attributes={}; value=[]]]]