PHP使用DOMDocument 操作xml

<?php
class xmlMessage{
    protected $doc;
    protected $rootKey;//根节点
    public $xmlName;//xml文件名

    /*
    xmlMessage类构造函数
    @param string xmlName
    */
    public function  __construct($xmlName,$rootKey) {
        
        $this->xmlName=$xmlName;
        $this->rootKey = $rootKey;
        
        if(!file_exists($this->xmlName))
         {
            $this->doc = new DOMDocument('1.0', 'utf-8');
            $rootKey = $this->doc->createElement($this->rootKey);//create root key
            $this->rootKey = $this->doc->appendChild($rootKey);
            $this->doc->save($this->xmlName);
         }else
         {
            $this->doc = new DOMDocument();            
            $this->doc->load($xmlName);

         }
         
            $this->doc->formatOutput = true;
    
        }
    

    /*
     创建子节点
     @param $childNode :要创建的子节点及属性$child_attr_array=null；    
     @param $parentNode：要创建的子节点的父节点及属性 $parent_attr_array=null；
    */
    public function createChildNode($childNode,$child_attr_array=null,$parentNode,$parent_attr_array=null)
    {
        $cnode = $this->doc->createElement($childNode);

        //获取要添加的子节点的父节点
        if($parent_attr_array!=null){
            foreach($parent_attr_array as $attr_key=>$attr_value)
            {
                $cnode = $this->getNodeByAttr($parentNode,$attr_key,$attr_value)->appendChild($cnode);
            }
        }else
        {        //避免创建父节点即：在父节点下创建子节点    
                $cnode = $this->doc->getElementsByTagName($parentNode)->item(0)->appendChild($cnode);
        }

        
           //设置子节点值
        //$cnode->nodeValue=$chileNodeValue;

        //设置属性
        if($child_attr_array!=null)
        {
            foreach($child_attr_array as $attr_key=>$attr_value)
            {
                $cnode->setAttribute($attr_key,$attr_value);
            }
        }



    }

    /*
      获取具有某属性的节点
      @param 节点名$nodeName,及其属性和值$attrName,$attrValue
      @return DOMNode 
    */
    public function getNodeByAttr($nodeName,$attrName,$attrValue)
    {
        $nodeList = $this->doc->getElementsByTagName($nodeName);

        for($i=0; $i<$nodeList->length;$i++)
        {
            $attrList = $nodeList->item($i)->getAttributeNode($attrName);
            if($attrList->value == $attrValue)
            {
                return $nodeList->item($i);
                
                //echo 'okkkkkk'.'<br>';;
            }
       
        }
        
    }
    

    //删除具有某个属性的节点
    public function delete_Node($nodeName,$attrName,$attrValue)
    {
        try
        {
           $delete_Node = $this->getNodeByAttr($nodeName,$attrName,$attrValue);
           $delete_Node->parentNode->removeChild($delete_Node);

        }catch(DOMException $e)
        {
            echo 'fail!';
        }
    }


    //创建节点属性
    public function createNodeAttribute($nodeName,$attr,$aValue)
    {
         $nodes = $this->doc->getElementsByTagName($nodeName);
          for($i=0; $i<$nodes->length;$i++)
        {
          $nodeValue = $nodes->item($i)->nodeValue.'<br>';
        }
        
        //$node->item[0]->setAttribute($attr,$aValue);

    }

    /*
     保存xml
    */
    public function saveXml()
        {
           
           $this->doc->save($this -> xmlName);
        }



   

}

//实例操作
  $myXml = new xmlMessage("opera.xml","世界");//创建一个以"世界"为根节点的xml文件
 
  $myXml->createChildNode("国家",array('name'=>'中国','人口'=>'1亿'),'世界');

  $myXml->createChildNode("国家",array('name'=>'英国','人口'=>'50millon'),'世界');

  $myXml->createChildNode("山东",array('city'=>'济南','note'=>'省会'),'国家',array('name'=>'英国'));
  $myXml->createChildNode("浙江",'','国家',array('name'=>'英国'));

  //$myXml->createChildNode("历城",array('city'=>'济南','note'=>'区'),'山东');


  //$myXml->createNodeAttribute("国家","人口",125);

  //$myXml->getNodeByAttr("国家",'name','英国');
  //$myXml->delete_Node("历城",'city','济南');


  $myXml->saveXml();

?>