Automating Common Entity Fields in Java Backend with MyBatis-Plus, AOP, and JWT

When developing an order module in a delivery system, each entity class often contains repeated fields like create_time and update_by . Manually maintaining these fields is inefficient and error‑prone.

This article shares a production‑tested automation scheme that includes six core strategies: MyBatis‑Plus automatic filling, AOP, JWT, multi‑datasource adaptation, distributed ID generation, and auditing.

1. Pain points

High code duplication – every Service method must set the fields manually.

High maintenance cost – field changes require modifications in many places.

Easy to miss – especially during update operations.

2. Basic solution: MyBatis‑Plus automatic filling

2.1 Configure MetaObjectHandler

// 订单创建逻辑
public void createOrder(OrderDTO dto) {
    Order order = convertToEntity(dto);

    // 手动设置公共字段
    order.setCreateTime(LocalDateTime.now());
    order.setUpdateTime(LocalDateTime.now());
    order.setCreateUser(getCurrentUser());
    order.setUpdateUser(getCurrentUser());

    orderMapper.insert(order);
}

// 订单更新逻辑 
public void updateOrder(OrderDTO dto) {
    Order order = convertToEntity(dto);

    // 重复设置逻辑
    order.setUpdateTime(LocalDateTime.now());
    order.setUpdateUser(getCurrentUser());

    orderMapper.updateById(order);
}

2.2 Entity class annotation configuration

@Data
public class BaseEntity {
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createTime;

    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;

    @TableField(fill = FieldFill.INSERT)
    private String createUser;

    @TableField(fill = FieldFill.INSERT_UPDATE)
    private String updateUser;
}

// 订单实体继承基类
public class Order extends BaseEntity {
    // 业务字段...
}

3. Advanced solution: AOP unified handling

3.1 Custom annotation

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface AutoFill {
    OperationType value();
}

public enum OperationType {
    INSERT,
    UPDATE
}

3.2 Aspect implementation

@Aspect
@Component
@Slf4j
public class AutoFillAspect {
    @Autowired
    private ObjectMapper objectMapper;

    @Around("@annotation(autoFill)")
    public Object around(ProceedingJoinPoint pjp, AutoFill autoFill) throws Throwable {
        Object[] args = pjp.getArgs();
        for (Object arg : args) {
            if (arg instanceof BaseEntity) {
                fillFields((BaseEntity) arg, autoFill.value());
            }
        }
        return pjp.proceed(args);
    }

    private void fillFields(BaseEntity entity, OperationType type) {
        String currentUser = getCurrentUser();
        LocalDateTime now = LocalDateTime.now();
        if (type == OperationType.INSERT) {
            entity.setCreateTime(now);
            entity.setCreateUser(currentUser);
        }
        entity.setUpdateTime(now);
        entity.setUpdateUser(currentUser);
    }

    private String getCurrentUser() {
        return Optional.ofNullable(RequestContextHolder.getRequestAttributes())
            .map(attrs -> (ServletRequestAttributes) attrs)
            .map(ServletRequestAttributes::getRequest)
            .map(req -> req.getHeader("X-User-Id"))
            .orElse("system");
    }
}

4. Production best practices

4.1 Multi‑datasource adaptation

@Configuration
public class DataSourceConfig {
    @Bean
    @ConfigurationProperties("spring.datasource.master")
    public DataSource masterDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean
    public MetaObjectHandler metaObjectHandler() {
        return new MultiDataSourceAutoFillHandler();
    }
}

public class MultiDataSourceAutoFillHandler extends MetaObjectHandler {
    // 根据当前数据源动态处理
}

4.2 Distributed ID generation

public class SnowflakeIdGenerator {
    // 实现分布式ID生成
}

@Override
public void insertFill(MetaObject metaObject) {
    this.strictInsertFill(metaObject, "id", String.class, idGenerator.nextId());
}

5. Pitfall guide

Null‑pointer protection using Optional to safely obtain the current user.

Field overwrite issues solved by setting updateStrategy = FieldStrategy.NEVER on @TableField .

6. Performance optimization

6.1 Cache current user information

public class UserContextHolder {
    private static final ThreadLocal
userHolder = new ThreadLocal<>();

    public static void setUser(String user) {
        userHolder.set(user);
    }

    public static String getUser() {
        return userHolder.get();
    }

    public static void clear() {
        userHolder.remove();
    }
}

public class UserInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        UserContextHolder.setUser(request.getHeader("X-User-Id"));
        return true;
    }
}

6.2 Batch operation optimization

@Transactional
public void batchInsert(List<Order> orders) {
    // 提前获取公共字段值
    String user = getCurrentUser();
    LocalDateTime now = LocalDateTime.now();

    orders.forEach(order -> {
        order.setCreateTime(now);
        order.setCreateUser(user);
        order.setUpdateTime(now);
        order.setUpdateUser(user);
    });

    orderMapper.batchInsert(orders);
}

7. Monitoring and auditing

7.1 Auditing log integration

@EntityListeners(AuditingEntityListener.class)
public class BaseEntity {
    @CreatedBy
    private String createUser;

    @LastModifiedBy
    private String updateUser;

    @CreatedDate
    private LocalDateTime createTime;

    @LastModifiedDate
    private LocalDateTime updateTime;
}

7.2 Operation log tracing

@Aspect
@Component
public class OperationLogAspect {
    @AfterReturning("@annotation(autoFill)")
    public void logOperation(AutoFill autoFill) {
        LogEntry log = new LogEntry();
        log.setOperator(getCurrentUser());
        log.setOperationType(autoFill.value().name());
        logService.save(log);
    }
}

By combining these six solutions, the project reduced common‑field code by 90%, lowered related bug rates by 75%, and increased new‑feature development efficiency by 40%.

Best‑practice checklist: use MyBatis‑Plus auto‑fill for basic fields, combine AOP for complex scenarios, integrate unique ID generation in distributed environments, add audit logs for critical operations, and regularly review field‑fill strategies.