如何将以下ereg 语句转换为 preg_reple
$message = ereg_replace("http://([.]?[a-zA-Z0-9_/-])*", "<a href="\0" target="_blank">\0</a>", $message);
$message = ereg_replace("(^| |
)(www([.]?[a-zA-Z0-9_/-])*)", "\1<a href="http://\2" target="_blank">\2</a>", $message);