一段PHP异常

这是我写的一段代码，里面通过PHP异常功能，实现报错时显示出错代码所在行。当使用者操作出错时，截图给我，我可以很快得去追踪和排查错误！

public function added_business_submit(){

    try{

        extract($_POST);

        if(''==$title)          self::json(0,sprintf(ERROR_EMPTY,'工单标题'));

        if(''==$is_trusteeship) self::json(0,sprintf(ERROR_EMPTY,'服务器类别'));

        if(''==$eqroom_id)      self::json(0,sprintf(ERROR_EMPTY,'所在机房'));

        M()->startTrans();

        $com_info     = M('company')->where(array('com_qyuserid'=>$com_qyuserid))->find();

        $com_id       = $com_info['com_id'];

        $com_name     = $com_info['com_name'];

        if(empty($com_info)) throw new Exception(ERROR_NOTFOUND_USER);

        $data = array(

            'com_id'       => $com_id,

            'com_name'     => $com_name,

            'type'         => 1,

            'step'         => 1,

            'poster'       => self::$user['name'],

            'posttime'     => self::$datetime,

            'eqroom_name'  => D('EquipRoom')->get_eqroom_name($eqroom_id),

        );

        $data = array_merge($data,$_POST);

        $agent_id = M('working_agent')->add($data);

        if(false===$agent_id) throw new Exception(ERROR_SUBMIT);

        $result = D('StepLogAgent')->next_step($agent_id,$remark);

        if(false===$result) throw new Exception(ERROR_SUBMIT);

    }catch(Exception $e){

        M()->rollback();

        $this->exception_handle($e);

    }

    M()->commit();

    self::json(1,SUCCESS_SUBMIT);

}

private function exception_handle(Exception $e){

    $msg  = $e->getMessage();

    $line = $e->getLine();

    //**/print_r($e); echo M()->getLastSql();

    $name = self::$user['name'];

    $time = self::$datetime;

    $sql  = M()->getLastSql();

    $log  = $time." ".$name.":{$msg}({$line}) {$sql}";

    self::mylog($log,'Agent');

    self::json(0,"{$msg}({$line})");

}