我們在web項目中經(jīng)常需要在后臺對用戶提交的表單進行校驗防止重復(fù)提交。下面通過springboot的aop逼肯、redis來解決表單重復(fù)提交的問題。

通過在controller加上CheckSubmitForm注解 桃煎，用戶訪問連接時篮幢，aop進行代理攔截

    @PostMapping("/comment/add")
    @CheckSubmitForm(delaySeconds = 6)
    public MallTradeResult comment(@RequestBody SiteUserCommentDTO siteUserCommentDTO,@User UserDTO userDTO) {
        siteUserCommentDTO.setUserId(userDTO.getUicId());
        siteUserCommentDTO.setPhone(userDTO.getPhoneNumber());
        siteUserCommentDTO.setNickName(userDTO.getUserName());
        siteUserCommentDTO.setUserHeadImg(userDTO.getAvatarUrl());
        return siteCommentFacade.add(siteUserCommentDTO);
    }

• requesetDTO中加入formId字段，fromId可以是前端提交的fromId为迈，也可以是我們自己業(yè)務(wù)定義的一個關(guān)鍵字洲拇。fromId用做redis 的key

@Data
public class SiteUserCommentDTO  extends RequesetDTO{

    private String itemCode ;

    private String formId;

    public String getFormId() {
        return itemCode ;
    }
}

• CheckSubmitFrom 注解是攔截哪些請求對用戶提交的表單進行校驗
  作者項目中是使用 methodname:userId:formId來作為redis key奈揍。例如下圖實例key為comment:userId:itemCode 表示用戶userId對某件商品itemCode的評價comment。如果key存在則阻止提交赋续。也可以由前端傳遞formId直接作為key男翰。key業(yè)務(wù)范圍盡量要小，太大可能對用戶的其他表單提交有影響纽乱。

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface CheckSubmitForm {
    int delaySeconds() default 5;
}

• ReSubmitAspect 定義aop切面

/**
 * Description:
 *
 * @author lixj on 2019/10/11.
 */
@Slf4j
@Component
@Aspect
public class ReSubmitAspect {
    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    private String keyId = "formId";

    @Around("@annotation(com.fcbox.mall.web.support.CheckSubmitForm)")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable{
        log.info("resubmitApsec do around");
        MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
        CheckSubmitForm checkSubmitForm = methodSignature.getMethod().getAnnotation(CheckSubmitForm.class);

        if (checkSubmitForm == null) {
            return joinPoint.proceed();
        } else {
            Object[] args = joinPoint.getArgs();
            String formId = null;
            String userId = null;
            for (Object arg : args) {
                if (StringUtils.isEmpty(formId)) {
                    JSONObject jsonObject = JSONObject.parseObject(JSONObject.toJSONString(arg));
                    if (!StringUtils.isEmpty(jsonObject.getString(keyId))) {
                        formId = jsonObject.getString(keyId);
                    }
                }
                if (StringUtils.isEmpty(userId)) {
                    if (arg.getClass().getAnnotation(User.class) != null) {
                        UserDTO userDTO = (UserDTO)arg;
                        userId = userDTO.getUicId().toString();
                    }
                }

            }
            if (!StringUtils.isEmpty(formId) && !StringUtils.isEmpty(userId)) {
                Class<?> returnType = ((MethodSignature) joinPoint.getSignature()).getMethod().getReturnType();

                String redisKey = ((MethodSignature) joinPoint.getSignature()).getMethod().getName().concat(":").concat(userId)
                        .concat(":").concat(formId);
                log.info("resubmit {}", redisKey, checkSubmitForm.delaySeconds());
                boolean submitAble = stringRedisTemplate.opsForValue().setIfAbsent(redisKey, "1");
                if (!submitAble) {
                    long ttl = stringRedisTemplate.getExpire(redisKey);
                    if (ttl > 0) {
                            return MallTradeResult.fail(ResultCode.REPEAT_SUBMIT_ERROR.getCode(), ResultCode.REPEAT_SUBMIT_ERROR.getMsg());
                        }
                    }
                }
                stringRedisTemplate.expire(redisKey, checkSubmitForm.delaySeconds(), TimeUnit.SECONDS);
                return joinPoint.proceed();
            } else {
                log.error("重復(fù)表單提交檢驗 失效: 參數(shù)錯誤:fromId-{},uicId-{}",formId,userId);
            }

        }

        return joinPoint.proceed();
    }
}

** 注意：代碼中stringRedisTemplate的setNx 和 expire 不是原子操作蛾绎。可以使用lua腳本實現(xiàn)或者Jedis開源組件來實現(xiàn)原子操作鸦列。