以下代码可以从URL中获得域名

例如:http://souzz.net/html/database/ORACLE/69613.html

得到souzz.net

function get_do($url){
  $pattern = "/[\w-]+\.(com|net|org|gov|cc|biz|info|cn)(\.(cn|hk))*/";
  preg_match($pattern, $url, $matches);
  (count($matches) > 0) {
   $matches[0];
  }{
   $rs = parse_url($url);
   $_url = $rs["host"];
   (!strcmp(long2ip(sprf("%u",ip2long($_url))),$_url)) {
    $_url;
   }{
    $arr = explode(".",$_url);
    $count=count($arr);
    $endArr = .gif' />("com","net","org","3322");//com.cn  net.cn 等情况
    (in_.gif' />($arr[$count-2],$endArr)){
     $do = $arr[$count-3].".".$arr[$count-2].".".$arr[$count-1];
    }{
     $do =  $arr[$count-2].".".$arr[$count-1];
    }
    $do;
   }// end (!strcmp...)
  }// end (count...)
 }// end function