@Transactional 无法回滚
@Transactional()
public void insertTow(){
Girl g1 =new Girl();
g1.setCupSize("A");
g1.setAge(10);
girlRepository.save(g1);
Girl g2 =new Girl();
g2.setCupSize("2dd");
g2.setAge(10);
girlRepository.save(g2);
}