SpringBoot - 公共字段自动填充的6种方案

01痛点速览

// 每写一个 Service 就要来一遍
order.setCreateTime(LocalDateTime.now());
order.setUpdateTime(LocalDateTime.now());
order.setCreateUser(getCurrentUser());
order.setUpdateUser(getCurrentUser());

总结：

1. Ctrl C + Ctrl V 到手抽筋
2. 一改字段，全局爆炸
3. 一不留神就漏填

02方案 1MyBatis-Plus 元对象处理器

最香基础款

2.1 核心代码

@Slf4j
@Component
public class AutoFillHandler implements MetaObjectHandler {

    @Override
    public void insertFill(MetaObject metaObject) {
        // 新增时填充
        strictInsertFill(metaObject, "createTime", LocalDateTime.class, LocalDateTime.now());
        strictInsertFill(metaObject, "createUser", String.class, getCurrentUser());
        strictInsertFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
        strictInsertFill(metaObject, "updateUser", String.class, getCurrentUser());
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        // 更新时只刷新 update*
        strictUpdateFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
        strictUpdateFill(metaObject, "updateUser", String.class, getCurrentUser());
    }

    /** 从 Security 上下文里拿登录人 */
    private String getCurrentUser() {
        return Optional.ofNullable(SecurityContextHolder.getContext())
                       .map(SecurityContext::getAuthentication)
                       .map(Authentication::getName)
                       .orElse("system");
    }
}

注解：

1. 实现 MetaObjectHandler，MyBatis-Plus 会自动回调
2. strictInsertFill 只在 insert 语句里生效
3. 使用 Optional 防 NPE，稳！

2.2 实体类配上注解

@Data
public abstract 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;
}

@Entity
@Table(name = "t_order")
public class Order extends BaseEntity { }

03方案 2：AOP 切面

专治各种不服

3.1 自定义注解，声明式零侵入

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

public enum OperationType {
    INSERT, UPDATE
}

3.2 切面逻辑

@Aspect
@Component
@Slf4j
public class AutoFillAspect {

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

    private void fill(BaseEntity entity, OperationType type) {
        String user = getCurrentUser();
        LocalDateTime now = LocalDateTime.now();

        if (type == OperationType.INSERT) {
            entity.setCreateTime(now);
            entity.setCreateUser(user);
        }
        entity.setUpdateTime(now);
        entity.setUpdateUser(user);
    }

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

注解：

1. @Around 拦截所有标注 @AutoFill 的方法
2. 统一在进入方法前就把字段塞满
3. 支持多参数批量处理，一行注解搞定

04方案 3：分布式 ID + 多数据源

4.1 Snowflake 发号器

@Configuration
public class SnowflakeConfig {
    @Bean
    public SnowflakeIdWorker idWorker(@Value("${snowflake.workerId}") long workerId,
                                      @Value("${snowflake.dataCenterId}") long dataCenterId) {
        return new SnowflakeIdWorker(workerId, dataCenterId);
    }
}

4.2 多数据源下自动填充

public class MultiDataSourceAutoFillHandler extends MetaObjectHandler {

    @Autowired
    private SnowflakeIdWorker idWorker;

    @Override
    public void insertFill(MetaObject metaObject) {
        super.insertFill(metaObject);
        // 分布式主键
        strictInsertFill(metaObject, "id", Long.class, idWorker.nextId());
    }
}

05方案 4：性能优化三板斧

5.1 ThreadLocal 缓存当前用户

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

    public static void set(String user) { holder.set(user); }
    public static String get() { return holder.get(); }
    public static void clear() { holder.remove(); }
}

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

    @Override
    public void afterCompletion(...) {
        UserContextHolder.clear();   // 防止内存泄漏
    }
}

5.2 批量操作统一时间

@Transactional
public void batchInsert(List<Order> orders) {
    String user = UserContextHolder.get();
    LocalDateTime now = LocalDateTime.now();

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

    orderMapper.batchInsert(orders);
}

06方案 5：监控 + 审计

6.1 切面记录操作日志

@Aspect
@Component
public class OperationLogAspect {

    @AfterReturning("@annotation(autoFill)")
    public void log(AutoFill autoFill) {
        LogEntry log = new LogEntry();
        log.setOperator(UserContextHolder.get());
        log.setOperation(autoFill.value().name());
        log.setTime(LocalDateTime.now());
        logService.save(log);
    }
}

避坑指南

总结

MyBatis-Plus 打底，AOP 做加持，Snowflake 管 ID，ThreadLocal 提性能，切面搞审计