创建controller/service/mapper/impl过程

先创建entity包，在里面导入实体类

然后创建controller/mapper/service包

然后在service里创建impl包

然后在mapper包里写mapper接口，加上@Mapper注解，继承BaseMapper<Employee>，泛型是实体类

@Mapper
public interface EmployeeMapper extends BaseMapper<Employee> {
}

 由于继承，把常见增删改查都有了

然后创建service，继承IService<Employee>泛型是实体类

public interface EmployeeService extends IService<Employee> {
}

然后创建service的实现类，加上@Servise注解，extends ServiceImpl<>泛型是EmployeeMapper和Employee，实现implements EmployeeService

@Service
public class EmployeeServiceImpl extends ServiceImpl<EmployeeMapper, Employee> implements EmployeeService {
}

然后创建controller，访问路径注解，注入service

@Slf4j
@RestController
@RequestMapping("/employee")
public class EmployeeController {
    @Autowired
    private EmployeeService employeeService;
}