PHP 获取指定URl页面中所有链接

<?php//获取指定URL页面中所有链接  function get_url_href($url){      $html = file_get_contents($url);      $dom = new DOMDocument();      @$dom->loadHTML($html);      $xpath = new DOMXPath($dom);      $hrefs = $xpath->evaluate('/html/body//a');      $arr_urls = array();    for($i=0;$i<$hrefs->length;$i++){          $href = $hrefs->item($i);          $url = $href->getAttribute('href');          if(substr($url,0,4) == 'http') {           $arr_urls[] = $url;        }      }    return $arr_urls;  }$arr_urls = get_url_href("http://www.baonahao.com");echo "<pre/>";print_r($arr_urls);