PHP中通过$SERVER获取网址的路径

$_SERVER['HTTP_HOST'] 	//获取域名或主机地址
$_SERVER['SERVER_NAME']	//获取域名或主机地址，但不包括端口号
$_SERVER['SERVER_PORT']	//获取端口号
$_SERVER['HTTP_HOST'] = $SERVER_PORT['SERVER_NAME'].":".$_SERVER['SERVER_PORT']

//获取地址栏的完整路径
$url="http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
//或者
$url="http://".$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF']."?".$_SERVER['QUERY_STRING']

$_SERVER['PHP_SELF']	//返回文件路径
$_SERVER['QUERY_STRING']	//获取请求的参数。？后面的部分，不包括？