my $query = "SELECT * FROM users WHERE user=?";
my $sth = $dbh->prepare($query);
$sth->execute($user) or die $sth->errstr();

# Here you have all the user's info in a hashref. The
# keys are the same as the database column names.
my $row = $sth->fetchrow_hashref();
# Then you could call the new method:
my $user_info = User->new($row);
##</code><code>##

package User;

sub new {
     my($class,$user_info) = @_;
     return bless $user_info,$class;
}