自定义php类(查找/修改)xml文档_php技巧

/* 
 
<班级> 
<学生 number="101"> 
<名字>孙悟空 
<名字>孙行者 
<年龄>猴精猴精 
<介绍> 
 
<学生 number="102"> 
<名字>白骨精 
<年龄>140 
<介绍>幻化万千 
 
<学生 number="103"> 
<名字>猪八戒 
<名字>猪无能 
<年龄>200 
<介绍>能吃会睡 
 
 
*/ 
class xmlDom{ 
public $version; 
public $encoding; 
private $xml; 
private $items; 
private $seachNode = ''; 
private $seachItem = ''; 
private $seachValue = ''; 
public $writeBytes = 0; 
function __construct($xmlFile ='', $version ='1.0', $encoding = 'UTF-8'){ 
$this->version = $version; 
$this->encoding = $encoding; 
$this->xml = new DOMDocument($version, $encoding); 
if($xmlFile)$this->xml->load($xmlFile); 
} 
function getRootEle($rootTag){ 
$this->xmlRoot = $this->xml->getElementsByTagName($rootTag)->item(0); 
} 
function getSeachItem($itemsTag, $seachNode, $seachValue){ 
$this->items = $this->xml->getElementsByTagName($itemsTag); 
$this->items->length; 
for($i=0; $i<$this->items->length; $i++){ 
$item = $this->items->item($i);//元素 
$node = $item->getElementsByTagName($seachNode);//节点 
for($j = 0; $j< $node->length; $j++){ 
$subNode = $node->item($j); 
if($seachValue == $subNode->nodeValue){ 
$this->seachNode = $subNode; 
$this->seachItem = $item; 
$this->seachValue = $subNode->nodeValue; 
break(2); 
} 
} 
} 
return ($this->seachNode) ? true : false; 
} 
function update($nodeValue, $nodeTag = '',$append = false, $index = 0){ 
if($append){ 
if($nodeTag) 
$this->seachItem->getElementsByTagName($nodeTag)->item($index)->nodeValue += $nodeValue; 
else 
$this->seachNode->nodeValue += $nodeValue; 
}else{ 
if($nodeTag) 
$this->seachItem->getElementsByTagName($nodeTag)->item($index)->nodeValue = $nodeValue; 
else 
$this->seachNode->nodeValue = $nodeValue; 
} 
} 
function save($filename){ 
$this->writeBytes = $this->xml->save($filename); 
return ($this->writeBytes) ? true : false; 
} 
} 
$test = new xmlDom('student.xml'); 
$test->getSeachItem('学生','年龄','103');//找到 年龄=103 的猪八戒 
$test->update('小猪猪', '名字', false, 1); //把猪八戒的第二个名字改成：小猪猪 
$test->save('new.xml'); //保存成新文件