// 訂單創(chuàng)建邏輯
publicvoidcreateOrder(OrderDTO dto){
    Order order = convertToEntity(dto);
    
    // 手動(dòng)設(shè)置公共字段
    order.setCreateTime(LocalDateTime.now());
    order.setUpdateTime(LocalDateTime.now());
    order.setCreateUser(getCurrentUser());
    order.setUpdateUser(getCurrentUser());
    
    orderMapper.insert(order);
}

// 訂單更新邏輯 
publicvoidupdateOrder(OrderDTO dto){
    Order order = convertToEntity(dto);
    
    // 重復(fù)設(shè)置邏輯
    order.setUpdateTime(LocalDateTime.now());
    order.setUpdateUser(getCurrentUser());
    
    orderMapper.updateById(order);
}

@Slf4j
@Component
publicclassAutoFillHandlerimplementsMetaObjectHandler{
    
    // 插入時(shí)自動(dòng)填充
    @Override
    publicvoidinsertFill(MetaObject metaObject){
        this.strictInsertFill(metaObject, "createTime", LocalDateTime.class, LocalDateTime.now());
        this.strictInsertFill(metaObject, "createUser", String.class, getCurrentUser());
        this.strictUpdateFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
        this.strictUpdateFill(metaObject, "updateUser", String.class, getCurrentUser());
    }

    // 更新時(shí)自動(dòng)填充
    @Override
    publicvoidupdateFill(MetaObject metaObject){
        this.strictUpdateFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
        this.strictUpdateFill(metaObject, "updateUser", String.class, getCurrentUser());
    }
    
    // 獲取當(dāng)前用戶(hù)（從安全上下文）
    private String getCurrentUser(){
        return Optional.ofNullable(SecurityContextHolder.getContext())
                      .map(SecurityContext::getAuthentication)
                      .map(Authentication::getName)
                      .orElse("system");
    }
}

@Data
publicclassBaseEntity{
    @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;
}

// 訂單實(shí)體繼承基類(lèi)
publicclassOrderextendsBaseEntity{
    // 業(yè)務(wù)字段...
}

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

publicenum OperationType {
    INSERT,
    UPDATE
}

@Aspect
@Component
@Slf4j
publicclassAutoFillAspect{
    
    @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);
    }

    privatevoidfillFields(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);
    }
    
    // 獲取當(dāng)前用戶(hù)（支持多線(xiàn)程環(huán)境）
    private String getCurrentUser(){
        return Optional.ofNullable(RequestContextHolder.getRequestAttributes())
                      .map(attrs -> (ServletRequestAttributes) attrs)
                      .map(ServletRequestAttributes::getRequest)
                      .map(req -> req.getHeader("X-User-Id"))
                      .orElse("system");
    }
}

@Configuration
publicclassDataSourceConfig{
    
    @Bean
    @ConfigurationProperties("spring.datasource.master")
    public DataSource masterDataSource(){
        return DataSourceBuilder.create().build();
    }
    
    @Bean
    public MetaObjectHandler metaObjectHandler(){
        returnnew MultiDataSourceAutoFillHandler();
    }
}

publicclassMultiDataSourceAutoFillHandlerextendsMetaObjectHandler{
    // 根據(jù)當(dāng)前數(shù)據(jù)源動(dòng)態(tài)處理
}

publicclassSnowflakeIdGenerator{
    // 實(shí)現(xiàn)分布式ID生成
}

// 在自動(dòng)填充中集成
@Override
publicvoidinsertFill(MetaObject metaObject){
    this.strictInsertFill(metaObject, "id", String.class, 
        idGenerator.nextId());
}

// 使用Optional處理可能為空的情況
private String safeGetUser(){
    return Optional.ofNullable(SecurityContextHolder.getContext())
                 .map(SecurityContext::getAuthentication)
                 .map(Authentication::getPrincipal)
                 .map(principal -> {
                     if (principal instanceof UserDetails) {
                         return ((UserDetails) principal).getUsername();
                     }
                     return principal.toString();
                 })
                 .orElse("system");
}

// 在實(shí)體類(lèi)中使用@TableField策略
@TableField(fill = FieldFill.INSERT, updateStrategy = FieldStrategy.NEVER)
private String createUser;

publicclassUserContextHolder{
    privatestaticfinal ThreadLocal<String> userHolder = new ThreadLocal<>();
    
    publicstaticvoidsetUser(String user){
        userHolder.set(user);
    }
    
    publicstatic String getUser(){
        return userHolder.get();
    }
    
    publicstaticvoidclear(){
        userHolder.remove();
    }
}

// 在攔截器中設(shè)置
publicclassUserInterceptorimplementsHandlerInterceptor{
    @Override
    publicbooleanpreHandle(HttpServletRequest request, 
                            HttpServletResponse response, 
                            Object handler){
        UserContextHolder.setUser(request.getHeader("X-User-Id"));
        returntrue;
    }
}

@Transactional
publicvoidbatchInsert(List<Order> orders){
    // 提前獲取公共字段值
    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);
}

@EntityListeners(AuditingEntityListener.class)
publicclassBaseEntity{
    @CreatedBy
    private String createUser;
    
    @LastModifiedBy
    private String updateUser;
    
    @CreatedDate
    private LocalDateTime createTime;
    
    @LastModifiedDate
    private LocalDateTime updateTime;
}

@Aspect
@Component
publicclassOperationLogAspect{
    
    @AfterReturning("@annotation(autoFill)")
    publicvoidlogOperation(AutoFill autoFill){
        LogEntry log = new LogEntry();
        log.setOperator(getCurrentUser());
        log.setOperationType(autoFill.value().name());
        logService.save(log);
    }
}