springboot 记录数据修改前和修改后的记录返回给前端

可以使用 Spring AOP 的方式，在数据更新时拦截相关方法，将数据修改前后的差异信息记录下来，然后将记录返回给前端。以下是简单的代码示例：

首先定义一个切面类，用于拦截数据更新方法：

@Aspect
@Component
public class DataChangeAspect {
 
    @Autowired
    private HttpServletRequest request;
 
    @Pointcut("execution(public * com.example.demo.service.*.update*(..))")
    public void updatePointcut() {}
 
    @Around("updatePointcut()")
    public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {
        // 获取方法名
        String methodName = joinPoint.getSignature().getName();
        // 获取参数列表
        Object[] args = joinPoint.getArgs();
        // 获取被更新的实体对象
        Object entityObject = args[0];
        // 获取原始实体对象
        Object originalObject = getOriginalEntityObject(entityObject);
        // 执行方法
        Object result = joinPoint.proceed();
        // 记录数据差异并返回给前端
        recordDataChange(originalObject, entityObject);
        return result;
    }
 
    /**
     * 获取原始实体对象
     */
    private Object getOriginalEntityObject(Object entityObject) {
        // 根据实体对象的 ID 查询原始实体对象
        // 这里需要根据具体业务进行实现
        Long entityId = ((BaseEntity) entityObject).getId();
        return entityManager.find(entityObject.getClass(), entityId);
    }
 
    /**
     * 记录数据差异并返回给前端
     */
    private void recordDataChange(Object originalObject, Object entityObject) {
        // 计算数据差异
        Map<String, Object> diffMap = getDiff(originalObject, entityObject);
        // 将差异信息记录到日志中
        String diffStr = convertDiffMapToString(diffMap);
        logService.info("数据修改前后差异：" + diffStr);
        // 将差异信息返回给前端
        request.setAttribute("dataDiff", diffMap);
    }
 
    /**
     * 计算实体对象的属性差异信息
     */
    private Map<String, Object> getDiff(Object originalObject, Object entityObject) {
        Map<String, Object> diffMap = new HashMap<>();
        Class<?> clazz = entityObject.getClass();
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields) {
            // 非持久化字段不参与差异计算
            if (!field.isAnnotationPresent(Column.class)) {
                continue;
            }
            String fieldName = field.getName();
            Object originalValue = ReflectionUtils.getFieldValue(originalObject, fieldName);
            Object newValue = ReflectionUtils.getFieldValue(entityObject, fieldName);
            if (originalValue == null || !originalValue.equals(newValue)) {
                diffMap.put(fieldName, newValue);
            }
        }
        return diffMap;
    }
 
    /**
     * 将差异信息转换为字符串
     */
    private String convertDiffMapToString(Map<String, Object> diffMap) {
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<String, Object> entry : diffMap.entrySet()) {
            sb.append(entry.getKey()).append(": ").append(entry.getValue()).append(",");
        }
        if (sb.length() > 0) {
            sb.deleteCharAt(sb.length() - 1);
        }
        return sb.toString();
    }
}

然后，使用 AOP 拦截 Spring Data JPA 的 save 或 update 方法：

@Aspect
@Component
public class JpaRepositoryAspect {
 
    @Autowired
    private HttpServletRequest request;
 
    @Around("execution(public * org.springframework.data.jpa.repository.JpaRepository+.save(..)) || execution(public * org.springframework.data.jpa.repository.JpaRepository+.saveAndFlush(..))")
    public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {
        // 获取被保存或更新的实体对象
        Object entityObject = joinPoint.getArgs()[0];
        // 记录数据变化并返回给前端
        request.setAttribute("originalData", entityObject);
        Object result = joinPoint.proceed();
        request.setAttribute("modifiedData", entityObject);
        return result;
    }
}

最后，在 Controller 中获取前面拦截器中记录的数据差异信息和修改前后的实体对象：

@RestController
public class DataController {
 
    @GetMapping("/users/{userId}")
    public User getUser(@PathVariable Long userId, HttpServletRequest request) {
        // 查询用户
        User user = userRepository.findById(userId).orElse(null);
        // 获取数据差异信息
        Map<String, Object> dataDiff = (Map<String, Object>) request.getAttribute("dataDiff");
        // 获取修改前的实体对象
        User originalData = (User) request.getAttribute("originalData");
        // 获取修改后的实体对象
        User modifiedData = (User) request.getAttribute("modifiedData");
        // 合并差异信息到修改后的实体对象中
        mergeDiffIntoModifiedData(modifiedData, dataDiff);
        return modifiedData;
    }
 
    /**
     * 将数据差异合并到修改后的实体对象中
     */
    private void mergeDiffIntoModifiedData(User modifiedData, Map<String, Object> dataDiff) {
        if (dataDiff == null || dataDiff.isEmpty()) {
            return;
        }
        BeanWrapper beanWrapper = PropertyAccessorFactory.forBeanPropertyAccess(modifiedData);
        beanWrapper.setAutoGrowNestedPaths(true);
        for (Map.Entry<String, Object> entry : dataDiff.entrySet()) {
            String fieldName = entry.getKey();
            Object value = entry.getValue();
            beanWrapper.setPropertyValue(fieldName, value);
        }
    }
}