simplexml_import_dom()

(PHP 5, PHP 7)

Get aSimpleXMLElementobject from a DOM node

说明

simplexml_import_dom(DOMNode$node[,string $class_name= "SimpleXMLElement"]): SimpleXMLElement

This function takes a node of a DOM document and makes it into a SimpleXML node. This new object can then be used as a native SimpleXML element.

参数

$node: A DOM Element node
$class_name: You may use this optional parameter so that simplexml_import_dom() will return an object of the specified class. That class should extend the SimpleXMLElement class.

返回值

Returns a SimpleXMLElement或者在失败时返回FALSE.

Warning
此函数可能返回布尔值FALSE，但也可能返回等同于FALSE的非布尔值。请阅读布尔类型章节以获取更多信息。应使用===运算符来测试此函数的返回值。

范例

Example #1 Importing DOM

<?php
$dom = new DOMDocument;
$dom->loadXML('<books><book><title>blah</title></book></books>');
if (!$dom) {
    echo 'Error while parsing the document';
    exit;
}
$s = simplexml_import_dom($dom);
echo $s->book[0]->title;
?>

以上例程会输出：

blah

参见

dom_import_simplexml()Gets a DOMElement object from a SimpleXMLElement object
Basic SimpleXML usage

/*If tags in DOM have text and some part of this text is surrounded by other tag, simple_import_dom object doesn't contain position of child tag, so rendering it back to html/xml can be a problem. Printing such a node is also peculiar. Eg.*/
//////////////////////
$text = "<body><p>Some text before <em>italic </em>and after text.</p></body>";
$dom = new DOMDocument;
$dom->loadHTML($text);
$result = simplexml_import_dom($dom);
echo $result->p;
//////////////////////
//Prints :
//Some text before and after text.
print_r($result->p);
//Prints:
//SimpleXMLElement Object ( [em] => italic )
print_r($result->p->em)
//does more or less the same:
//SimpleXMLElement Object ( [0] => italic )
var_dump($result->p);
//Prints:
//object(SimpleXMLElement)#8 (1) { ["em"]=> string(7) "italic " }
var_dump($result->p->em)
//object(SimpleXMLElement)#9 (1) { [0]=> string(7) "italic " }
//but
echo $result->p->em;
//prints:
//italic

simplexml_import_dom() will accept DOMNodes or other SimpleXMLElements. This has a useful purpose if you are extending the SimpleXMLElement class and would prefer the xpath() method to return your class extension instead of basic SimpleXMLElements. For example:
class MySimpleXML extends SimpleXMLElement{
  public function xpath($xpath){ 
    $return = array();
    $simpleXmls = parent::xpath($xpath); // run SimpleXMLElement xpath, returning an array of SimpleXMLElements
    foreach($simpleXmls as $xml){
      $return[] = simplexml_import_dom($xml,'MySimpleXML'); // copy SimpleXMLElement, returning as MySimpleXML instance
    }
    return $return;
  }
}
Now I can create an instance of MySimpleXML, run an xpath, and get my results back as an array of MySimpleXML elements instead of the native SimpleXMLElement:
$mySimpleXml = new mySimpleXml('<root><node/></root>');
$array = $mySimpleXml->xpath('/root/node'); // returns array with a single MySimpleXml object