//截取摘要public static function mbsubstr($str){  $strleng = mb_strlen($str,"utf8");  $mbstr = mb_substr($str,0,140,'utf8');  $strdstr = mb_substr($str,140,$strleng,'utf8');  $strlengs = mb_strlen($strdstr,'utf8');  $strc = "";  for($i=0;$i<$strlengs;$i++){    $strn = mb_substr($strdstr,$i,1,'utf8');    if($strn == "。" || $strn == "？" || $strn == "！"){      break;    }    $strc .= $strn;  }  $strd = $mbstr.$strc;  //echo $strleng."@".mb_strlen($strd,'utf8')."@".$strd."<br>";  return $strd;}