方法一：

private static $_user_name_arr = [];
private function getUserNameByUid($uid)
{
    if(!isset(self::$_user_name_arr[$uid])){
        $user =  DB::name("user")->find();
        self::$_user_name_arr[$uid] = $user?$user['name']:'';
    }
    return self::$_user_name_arr[$uid];
}

方法二：

static $locationtimes  = array();
public static function getLocationTimes($uid, $dayTime)
{
    if(!self::$locationtimes){
        $data = DB::name("user")->select();
        foreach ($data as $v) {
            self::$locationtimes[$v['uid']][]=$v;
        }
    }
    return isset(self::$locationtimes[$uid])?self::$locationtimes[$uid]:[];
}