实体类中id
/**
 * 指定自增策略
 */
@TableId(value = "id",type = IdType.AUTO)
private int id;

service层中

@Service
public class InformationService extends ServiceImpl<InformationMapper,Information> {

    @Autowired
    private InformationMapper informationMapper;

    public  int add(Information information){
        return  informationMapper.insert(information);
    }

}