php实现的一个很好用HTML解析器类可用于采集数据

<?php   $oldSetting = libxml_use_internal_errors( true );   libxml_clear_errors();  /** *  * -+----------------------------------- * |PHP5 Framework - 2011 * |Web Site: www.iblue.cc * |E-mail: [e-mail] * |Date: 2012-10-12 * -+----------------------------------- *  * @desc HTML解析器 * @author jingke */   class XF_HtmlDom  {      private $_xpath = null;      private $_nodePath = '';      public function __construct($xpath = null, $nodePath = '')      {          $this->_xpath = $xpath;          $this->_nodePath = $nodePath;      }      public function loadHtml($url)      {          ini_set('user_agent', 'Mozilla/5.0 (Linux; U; Android 2.1; en-us; Nexus One Build/ERD62) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Mobile Safari/530.17 –Nexus');          $content = '';          if(strpos(strtolower($url), 'http')===false)          {              $content = file_get_contents($url);          }          else         {              $ch = curl_init();               $user_agent = "Baiduspider+(+http://www.baidu.com/search/spider.htm)";              $user_agent1='Mozilla/5.0 (Windows NT 5.1; rv:6.0) Gecko/20100101 Firefox/6.0';              curl_setopt($ch, CURLOPT_URL, $url);               curl_setopt($ch, CURLOPT_HEADER, false);               curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);               curl_setopt($ch, CURLOPT_REFERER, $url);              curl_setopt($ch, CURLOPT_USERAGENT, $user_agent1);              curl_setopt($ch, CURLOPT_FOLLOWLOCATION,1);              $content =curl_exec($ch);               curl_close($ch);          }          $html = new DOMDocument();           $html->loadHtml($content);           $this->_xpath = new DOMXPath( $html );           //return $this;     }      public function find($query, $index = null)      {          if($this->_nodePath == '')              $this->_nodePath = '//';         else             $this->_nodePath .= '/';          $nodes = $this->_xpath->query($this->_nodePath.$query);          //echo $nodes->item(0)->getNodePath();exit;                   if ($index == null && !is_numeric($index))           {               $tmp = array();              foreach ($nodes as $node)               {                  $tmp[] = new XF_HtmlDom($this->_xpath, $node->getNodePath());              }              return $tmp;          }          return new XF_HtmlDom($this->_xpath,$this->_xpath->query($this->_nodePath.$query)->item($index)->getNodePath());      }      //unity3d论坛http://www.unitymanual.com/forum.php     /**     * 获取内容     */     public function text()      {          if ($this->_nodePath != '' && $this->_xpath != null )               return $this->_xpath->query($this->_nodePath)->item(0)->textContent;          else             return false;      }      /**     * 获取属性值     */     public function getAttribute($name)      {          if ($this->_nodePath != '' && $this->_xpath != null )               return $this->_xpath->query($this->_nodePath)->item(0)->getAttribute($name);          else             return false;      }      //http://www.unitymanual.com/sitemap.xml    public function __get($name)      {          if($name == 'innertext')              return $this->text();          else             return $this->getAttribute($name);      }    }    $xp = new xf_HtmlDom();  $xp->loadHtml('http://www.aizhan.com/siteall/www.opendir.cn/'); $rows = $xp->find("td[@id='baidu']/a", 0)->innertext;  print_r($rows);