PHP DOMDocument实现XML读写操作

$doc = new DOMDocument();  
$doc->load('test.xml');  
$rows = $doc->getElementsByTagName("ds");  
$d = array();  
$i = 0;  
foreach($rows as $row)  
{  
   $web     = $row->getElementsByTagName('web');  
   $webUrl  = $row->getElementsByTagName('webUrl');  
   $d[$i]['web']    = $web->item(0)->nodeValue;  
   $d[$i]['webUrl'] = $webUrl->item(0)->nodeValue;  
   $i++;  
}  
print_R($d);

$xmlData = file_get_contents('test.xml');  
$xml = simplexml_load_string($xmlData);  
$xmlArr = objectToArray($xml);

function objectToArray($object)  
{    
   if(!$object) return '';  
   $result = array();    
   $object = is_object($object) ? get_object_vars($object) : $object;    
   foreach ($object as $key => $val) {    
       $val = (is_object($val) || is_array($val)) ? objectToArray($val) : $val;    
       $result[$key] = $val;    
   }    
   return $result;    
}

$arr = array(  
    array('id'=>1,'web'=>'好脚本','webUrl'=>'http://www.phprm.com'),  
    array('id'=>2,'web'=>'PHP脚本','webUrl'=>'http://www.phprm.com/'),  
    array('id'=>3,'web'=>'JavaScript脚本','webUrl'=>'http://www.phprm.com/'),  
    array('id'=>4,'web'=>'js脚本','webUrl'=>'http://www.phprm.com/'),  
    array('id'=>5,'web'=>'PHP脚本示例','webUrl'=>'http://www.phprm.com/'),  
    array('id'=>5,'web'=>'JavaScript脚本示例','webUrl'=>'http://www.phprm.com/')  
);  
/*使用dom生成xml,注意生成的xml中会没有空格。*/ 
$dom=new DOMDocument('1.0','utf-8');  
$path= "logs/test.xml";  
$data=$dom->createElement('data');  
$dom->appendChild($data);  
foreach($arr as $v)  
{  
    $ds = $dom->createElement('ds');  
    $id = $dom->createAttribute('id');   
    $id->nodeValue = $v['id'];  
    $ds->setAttributeNode($id);  
    $data->appendChild($ds);  
    foreach($v as $kk=>$vv)  
    {  
       ${$kk} = $dom->createElement($kk);   
       $value= $dom->createTextNode($vv);  
       ${$kk}->appendChild($value);  
       $ds->appendChild(${$kk});  
    }  
}  
$dom->saveXML();  
$dom->save($path);