How to write XML self closing tag using DomDocument

问题

I am working with PHP generate XML, I am using DomDocument to generate XML tags, How Can I created Self Closing Tag using DomDocument??

$doc2 = new DOMDocument();
$root2 = $doc2->createElement('root', '');

Expected Output:

<?xml version="1.0"?><root/>

Actual result:

<?xml version="1.0"?><root></root>

Is there any other way to generate Self-Closing Tag?

PS: Please don't close the Question as I don't think this is a duplicate. Thanks.

回答1:

Providing the empty string second argument to createElement() adds an empty textnode to the element node. The element is not empty an can not be optimized. Without the argument DOM optimizes the XML.

$dom = new DOMDocument();
$dom->appendChild($dom->createElement('root'));
echo $dom->saveXml();

Output:

<?xml version="1.0"?>
<root/>

Here is an option for saveXml() to avoid the optimization.

$dom = new DOMDocument();
$dom->appendChild($dom->createElement('root'));
echo $dom->saveXml(NULL, LIBXML_NOEMPTYTAG);

Output:

<?xml version="1.0"?>
<root></root>

来源：https://stackoverflow.com/questions/23622858/how-to-write-xml-self-closing-tag-using-domdocument