简单分布式锁解决表单重复提交

前端按钮点击很快，有没有做置灰处理，反正后端不应该相信前端吧。

比如一下 添加接口 ，快速点击 可能会出现 两条重复数据，没有做唯一索引的话。

解决思路

1. 定义一个小注解
2. 定义一个切面

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface NotRepeatedSubmit {
    String msg() default "请勿重复提交";
}

@Aspect
@Component
public class NotRepeatedSubmitAspect {

    private static final String LOCK_REPEATED_SUBMIT = "lock_repeated_submit:";
    @Autowired
    private RedissonClient redissonClient;

    @Around("@annotation(notRepeatedSubmit)")
    public Object around(ProceedingJoinPoint pjp, NotRepeatedSubmit notRepeatedSubmit) throws Throwable {
        try {
            //获取当前执行类
            String className = pjp.getSignature().getDeclaringTypeName();
            //获取当前执行类中的执行方法
            String methodName = pjp.getSignature().getName();
            // 参数
            Map<String, Object> params = getRequestParams(pjp);
            String md5 = SecureUtil.md5(className + methodName + JSON.toJSONString(params));
            RLock lock = redissonClient.getLock(LOCK_REPEATED_SUBMIT+md5);
            boolean tryLock = lock.tryLock();
            if(tryLock){
                try {
                    Object result = pjp.proceed();
                    return result;
                } finally {
                    lock.unlock();
                }
            }
            throw new BusinessException(notRepeatedSubmit.msg());
        } catch (Throwable e) {
            throw e;
        }
    }


    /**
     * 获取入参
     * @param proceedingJoinPoint
     *
     * @return
     * */
    private Map<String, Object> getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
        Map<String, Object> requestParams = new HashMap<>();
        //参数名
        String[] paramNames =
                ((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
        //参数值
        Object[] paramValues = proceedingJoinPoint.getArgs();

        for (int i = 0; i < paramNames.length; i++) {
            Object value = paramValues[i];
            //如果是文件对象
            if (value instanceof MultipartFile) {
                MultipartFile file = (MultipartFile) value;
                //获取文件名
                value = file.getOriginalFilename();
            }

            if(value instanceof HttpServletResponse){
                continue;
            }
            if(value instanceof HttpServletRequest){
                continue;
            }
            requestParams.put(paramNames[i], value);
        }
             // 附加用户信息
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
        String principal = "";
        if(null != authentication){
            principal = authentication.getName();
        }
        requestParams.put("username",principal);
        return requestParams;
    }
}

使用 就在方法上打个注解