使用DOMdocument在XML文件中追加元素？

Question

i'm using the DOMdocument class in php whenever i want to create a XML document.

but how could i open a XML document and add elements after an existing element in the XML document?

its a very huge XML-document so it would be great to consider the most efficient way to do this.

Answer 1

If you're sticking with DOMdocument, appending a new node is as simple as getting a reference to an existing node, creating child nodes, and then appending new nodes to those children. I've used XPath below, but any method that returns a DOMNode should work. The important part to remember is even though you've fetched a part of the tree, internally it's part of the original DOMDocument.

$xml = new DomDocument();
$xml->loadXml('<foo><baz><bar>Node Contents</bar></baz></foo>');    

//grab a node
$xpath = new DOMXPath($xml);    
$results = $xpath->query('/foo/baz');   
$baz_node_of_xml = $results->item(0);

//create a new, free standing node  
$new_node = $xml->createElement('foobazbar');

//create a new, freestanding text node
$text_node = $xml->createTextNode('The Quick Brown Fox');

//add our text node
$new_node->appendChild($text_node);

//append our new node to the node we pulled out
$baz_node_of_xml->appendChild($new_node);

//output original document.  $baz_nod_of_xml is
//still considered part of the original $xml DomDocument
echo $xml->saveXML();