Need xml markup on persisting xml data to file using XmlParser

Question

After updating or adding something to an xml file, the xml declaration is removed. I am using XmlParser. Here is the code to update something in the xml.

def xml = new XmlParser().parseText(new File(fileLocation).getText('UTF-8'))
def found = xml.myTag1.findAll()
found.each{
     it.mySubTag.value="Updated"
}

XmlUtil.serialize(xml)
def nodePrinter = new XmlNodePrinter(new PrintWriter(new File(fileLocation)))
nodePrinter.preserveWhitespace=true
nodePrinter.print(xml)

Updating is successful btw. Only the problem is <?xml version="1.0" encoding="UTF-8"?> removed after updating.

Answer 1

Here is what you can do to achieve the same. Credits to @tim_yates. Just note the last line.

def xml = new XmlParser().parseText(new File(fileLocation).getText('UTF-8'))
def found = xml.myTag1.findAll()
found.each{
     it.mySubTag.value="Updated"
}

//Write content of updated xml into file with xml declaration
new File(fileLocation).write(groovy.xml.XmlUtil.serialize(xml))

If you want to write in utf-8?

new File(fileLocation).withWriter('UTF-8') { writer ->
    writer.write(groovy.xml.XmlUtil.serialize(xml))
}