解析xml文檔的一個簡單php類

<?PHP
//xml中的元素
class XMLTag
{
 var $parent;//父節點
 var $child;//子節點
 var $attribute;//本節點屬性
 var $data;//本節點資料
 var $TagName;//本節點名稱
 var $depth;//本節點的深度，根節點為1
 function XMLTag($tag='')
 {
  $this->attribute = array();
  $this->child = array();
  $this->depth = 0;
  $this->parent = null;
  $this->data = '';
  $this->TagName = $tag;
 }
 function SetTagName($tag)
 {
  $this->TagName = $tag;
 }
 function SetParent(&$parent)
 {
  $this->parent = &$parent;
 }
 function SetAttribute($name,$value)
 {
  $this->attribute[$name] = $value;
 }
 function AppendChild(&$child)
 {
  $i = count($this->child);
  $this->child[$i] = &$child;
 }
 function SetData($data)
 {
  $this->data= $data;
 }
 function GetAttr()
 {
  return $this->attribute;
 }
 function GetProperty($name)
 {
  return $this->attribute[$name];
 }
 function GetData()
 {
  return $this->data;
 }
 function GetParent()
 {
  return $this->parent;
 }
 function GetChild()
 {
  return $this->child;
 }
 function GetChildByName($name)
 {
  $total = count($this->child);
  for($i=0;$i<$total;$i++)
  {
   if($this->child[$i]->attribute['name'] == $name)
   {
    return $this->child[$i];
   }
  }
  return null;
 }
 //擷取某個tag節點
    function GetElementsByTagName($tag)
    {
     $vector = array();
     $tree = &$this;
     $this->_GetElementByTagName($tree,$tag,$vector);
     return $vector;
    }
    function _GetElementByTagName($tree,$tag,&$vector)
    {
     if($tree->TagName == $tag) array_push($vector,$tree);
     $total = count($tree->child);
     for($i = 0; $i < $total;$i++)
      $this->_GetElementByTagName($tree->child[$i],$tag,$vector);
    }
}
//xml文檔解析
class XMLDoc
{
 var $parser;//xml解析指標
 var $XMLTree;//產生的xml樹
 var $XMLFile;//將要解析的xml文檔
 var $XMLData;//將要解析的xml資料
 var $error;//錯誤資訊
 var $NowTag;//當前指向的節點
 var $TreeData;//遍曆產生的xml樹等到的資料
 var $MaxDepth;//本樹最大的深度
 var $encode;//xml文檔的編碼方式
 var $chs;//字元轉換
 function XMLDoc()
 {
  //採用預設的ISO-8859-1
  $this->parser = xml_parser_create();
  xml_parser_set_option($this->parser,XML_OPTION_CASE_FOLDING,0);
  xml_set_object($this->parser,&$this);
  xml_set_element_handler($this->parser,'_StartElement','_EndElement');
  xml_set_character_data_handler($this->parser,'_CData');
  $this->stack = array();
  $this->XMLTree = null;
  $this->NowTag = null;
  $this->MaxDepth = 0;
 }
 function LoadFromFile($file)
 {
  $this->XMLFile = fopen($file,'r');
  if(!$this->XMLFile)
  {
   $this->error = '不能開啟xml檔案';
   return false;
  }
  $this->XMLData = '';
  $this->TreeData = '';
  return true;
 }
 function SetXMLData($data)
 {
  if($this->XMLFile) fclose($this->XMLFile);
  $this->XMLData = $data;
  $this->TreeData = '';
 }
 //給樹添加一個新的節點
 function AppendChild(&$child)
 {
  if($this->XMLTree == null)
  {
   $child->depth = 1;
   $this->XMLTree = &$child;
   $this->NowTag = &$this->XMLTree;
  }
  else
  {
   $i = count($this->NowTag->child);
   $this->NowTag->child[$i] = &$child;
            $child->parent = &$this->NowTag;
   $child->depth = $this->NowTag->depth+1;
   unset($this->NowTag);
   $this->NowTag = &$child;
  }
  $this->MaxDepth = ($this->MaxDepth < $this->NowTag->depth)?$this->NowTag->depth:$this->MaxDepth;
 }

 //產生一個新的節點
 function &CreateElement($tag)
 {
  $element = new XMLTag($tag);
  return $element;
 }
 function _StartElement($parser,$element,$attribute)
 {
  $tag = new XMLTag();
  $tag->TagName = $element;
  $tag->attribute = $attribute;
  if($this->XMLTree == null)
  {
   $tag->parent = null;
   $tag->depth = 1;
   $this->XMLTree = &$tag;
   $this->NowTag = &$tag;
  }
  else
  {
   $i = count($this->NowTag->child);
   $this->NowTag->child[$i] = &$tag;
   $tag->parent = &$this->NowTag;
   $tag->depth = $this->NowTag->depth+1;
   unset($this->NowTag);
   $this->NowTag = &$tag;
  }
  $this->MaxDepth = ($this->MaxDepth < $this->NowTag->depth)?$this->NowTag->depth:$this->MaxDepth;
 }
 function _CData($paraser,$data)
 {
  $this->NowTag->data = $data;
 }
 function _EndElement($parser,$element)
 {
  $parent = &$this->NowTag->parent;
  unset($this->NowTag);
  $this->NowTag = &$parent;
 }
 //開始解析xml文檔
 function parse()
 {
  if($this->XMLFile)
  {
   $this->XMLData = '';
   while(!feof($this->XMLFile))
   {
    $this->XMLData .= fread($this->XMLFile,4096);
   }
  }
  fclose($this->XMLFile);
  if($this->XMLData)
  {
   //$this->JudgeEncode();
   if (!xml_parse($this->parser, $this->XMLData))
   {
    $code = xml_get_error_code($this->parser);
    $col = xml_get_current_column_number($this->parser);
    $line = xml_get_current_line_number($this->parser);
          $this->error = "XML error: $col at line $line:".xml_error_string($code);
          return false;
   }
  }
  xml_parser_free($this->parser);
  return true;
    }
    //確定編碼方式
    function JudgeEncode()
    {
     $start = strpos($this->XMLData,'<?xml');
     $end = strpos($this->XMLData,'>');
     $str = substr($this->XMLData,$start,$end-$start);
     $pos = strpos($str,'encoding');
     if($pos !== false)
     {
      $str = substr($str,$pos);
      $pos = strpos($str,'=');
      $str = substr($str,$pos+1);
      $pos = 0;
      while(empty($str[$pos])) $pos++;
      $this->encode = '';
      while(!empty($str[$pos]) && $str[$pos] != '?')
      {
       if($str[$pos] != '"' && $str[$pos] != "'")
        $this->encode .= $str[$pos];
       $pos++;
      }
     }
     $this->chs = new Chinese('UTF-8',$this->encode);
    }

    //根據節點名稱修改某個節點的值
    function ChangeValueByName($name,$name,$value)
    {
     return $this->_ChangeValueByName($this->XMLTree,$name,$value);
    }
    function _ChangeValueByName($tree,$name,$value)
    {
     if(is_array($tree->attribute))
     {
      while (list($k,$v) = each($tree->attribute))
      {
       if($k = 'name' && $v = $name)
       {
        $tree->data = $value;
        return true;
       }
      }
     }
     $total = count($tree->child);
     for($i = 0;$i<$total;$i++)
     {
      $result = $this->_ChangeValueByName($tree->child[$i],$name,$value);
      if($result == true) break;
     }
     return $result;
    }

    //根據節點名稱修改樹中某個節點的屬性
    function ChangeAttrByName($name,$attr,$value)
    {
     return $this->_ChangeAttrByName($this->XMLTree,$name,$attr,$value);
    }
    function _ChangeAttrByName(&$tree,$name,$attr,$value)
    {
     if(is_array($tree->attribute))
     {
      while(list($k,$v) = each($tree->atttibute))
      {
       if($k == 'name' && $v == $name)
       {
        $tree->attribute[$attr] = $value;
        return true;
       }
      }
     }
     $total = count($tree->child);
     for($i = 0;$i<$total;$i++)
     {
      $result = $this->_ChangeAttrByName($tree->child[$i],$name,$attr,$value);
      if($result == true) break;
     }
     return $result;
    }
    //擷取根節點
    function GetDocumentElement()
    {
     return $this->XMLTree;
    }
    //遍曆產生的xml樹,重建xml文檔
    function WalkTree()
    {
     $this->TreeData = '';
     $this->_WalkTree($this->XMLTree);
     return $this->TreeData;
    }
     //遞迴遍曆
    function _WalkTree($tree)
    {
     $this->TreeData .= '<'.$tree->TagName.' ';
     if(is_array($tree->attribute))
     {
      while(list($key,$value) = each($tree->attribute))
      {
       $this->TreeData .="$key=/"$value/" ";
      }
     }
     $this->TreeData .= '>'.$tree->data;
     $total = count($tree->child);
     for($i=0;$i<$total;$i++)
     {
      $this->_WalkTree($tree->child[$i]);
     }
     $this->TreeData .= '</'.$tree->TagName.">/n";
    }
    //擷取錯誤資訊
    function GetError()
    {
     return $this->error;
    }
    //擷取樹的最大深度
    function GetMaxDepth()
    {
     return $this->MaxDepth;
    }
    //將xml樹寫入xml檔案
    function WriteToFile($file,$head='')
    {
     $fp = fopen($file,'w');
     if(!$fp)
     {
      $this->error = '無法開啟寫入檔案';
      return false;
     }
     if(empty($this->TreeData)) $this->WalkTree();
     $head = empty($head)?'<?xml version="1.0" standalone="yes" encoding="gb2312"?>':$head;
     fwrite($fp,$head);
     fwrite($fp,$this->TreeData);
     fclose($fp);
     return true;
    }
}
?>