@Service
public class UserServiceImpl implements UserService {
 
   @Resource
   private UserMapper userMapper;
 
   @Override
   @Transactional(rollbackFor = Exception.class)
   public synchronized void isertUser(User user) {
       try {
           // 插入用户信息
           userMapper.insertUser(user);
           // 手动抛出异常
           throw new SQLException("数据库异常");
       } catch (Exception e) {
           // 异常处理逻辑
       }
   }
}