dom_import_simplexml()

(PHP 5, PHP 7)

Gets a DOMElement object from a SimpleXMLElement object

说明

dom_import_simplexml(SimpleXMLElement$node): DOMElement

This function takes the node$nodeof class SimpleXML and makes it into a DOMElement node. This new object can then be used as a native DOMElement node.

参数

$node

The SimpleXMLElement node.

返回值

The DOMElement node added or FALSE if any errors occur.

范例

Example #1 Import SimpleXML into DOM with dom_import_simplexml()

<?php
$sxe = simplexml_load_string('<books><book><title>blah</title></book></books>');
if ($sxe === false) {
    echo 'Error while parsing the document';
    exit;
}
$dom_sxe = dom_import_simplexml($sxe);
if (!$dom_sxe) {
    echo 'Error while converting XML';
    exit;
}
$dom = new DOMDocument('1.0');
$dom_sxe = $dom->importNode($dom_sxe, true);
$dom_sxe = $dom->appendChild($dom_sxe);
echo $dom->saveXML();
?>

参见

• simplexml_import_dom()Get a SimpleXMLElement object from a DOM node

SimpleXML is an 'Object Mapping XML API'. It is not DOM, per se. SimpleXML converts the XML elements into PHP's native data types.
The dom_import_simplexml and simplexml_import_dom functions do *not* create separate copies of the original object. You are free to use the methods of either or both interchangeably, since the underlying instance is the same.
<?php
  // initialize a simplexml object
  $sxe = simplexml_load_string('<root/>');
  
  // get a dom interface on the simplexml object
  $dom = dom_import_simplexml($sxe);
  // dom adds a new element under the root
  $element = $dom->appendChild(new DOMElement('dom_element'));
  
  // dom adds an attribute on the new element
  $element->setAttribute('creator', 'dom');
  // simplexml adds an attribute on the dom element
  $sxe->dom_element['sxe_attribute'] = 'added by simplexml';
  // simplexml adds a new element under the root
  $element = $sxe->addChild('sxe_element');
  
  // simplexml adds an attribute on the new element
  $element['creator'] = 'simplexml';
  // dom finds the simplexml element (via DOMNodeList->index)
  $element = $dom->getElementsByTagName('sxe_element')->item(0);
  // dom adds an attribute on the simplexml element
  $element->setAttribute('dom_attribute', 'added by dom');
  
  echo ('<pre>');      
  print_r($sxe);
  echo ('</pre>');
?>
Outputs:
SimpleXMLElement Object
(
  [dom_element] => SimpleXMLElement Object
    (
      [@attributes] => Array
        (
          [creator] => dom
          [sxe_attribute] => added by simplexml
        )
    )
  [sxe_element] => SimpleXMLElement Object
    (
      [@attributes] => Array
        (
          [creator] => simplexml
          [dom_attribute] => added by dom
        )
    )
)
What this illustrates is that both interfaces are operating on the same underlying object instance. Also, when you dom_import_simplexml, you can create and add new elements without reference to an ownerDocument (or documentElement).
So passing a SimpleXMLElement to another method does not mean the recipient is limited to using SimpleXML methods.
 
Hey Presto! Your telescope has become a pair of binoculars!

justinpatrin at php dot net:
> To get a proper DOM document (which you need to do most things) you need...
No you don't. Just do: 
<?php
$dom = dom_import_simplexml($xml)->ownerDocument;
?>

I've found that newer versions of PHP5 require some special syntax in order to properly convert between SimpleXML and DOM. It's not as easy as calling dom_import_simplexml() with a SimpleXML node. To get a proper DOM document (which you need to do most things) you need:
<?php
//$xml is a SimpleXML instance
$domnode = dom_import_simplexml($xml);
$dom = new DOMDocument();
$domnode = $dom->importNode($domnode, true);
$dom->appendChild($domnode);
?>
Switching back, though, is, well...simple.
<?php
//$dom is a DOMDocument instance
$xml = simplexml_import_dom($dom);
?>

Very useful to add a CDATA node with SimpleXMLElement (use it like addChild) :
<?php
class My_SimpleXMLElement extends SimpleXMLElement {
  
  public function addChildWithCData($name, $value = NULL) {
    $new_child = $this->addChild($name);
    
    $node = dom_import_simplexml($new_child); 
    $no = $node->ownerDocument; 
    $node->appendChild($no->createCDATASection($value)); 
  
    return $new_child;
  }
}