phpupdate语句累加技巧_8 种筹划帮你解决重复提交问题

/ @author lijing 重复提交锁 /@Slf4jpublic final class ResubmitLock { private static final ConcurrentHashMap LOCK_CACHE = new ConcurrentHashMap<>(200); private static final ScheduledThreadPoolExecutor EXECUTOR = new ScheduledThreadPoolExecutor(5, new ThreadPoolExecutor.DiscardPolicy); // private static final Cache CACHES = CacheBuilder.newBuilder // 最大缓存 100 个 // .maximumSize(1000) // 设置写缓存后 5 秒钟过期 // .expireAfterWrite(5, TimeUnit.SECONDS) // .build; private ResubmitLock { } / 静态内部类 单例模式 @return / private static class SingletonInstance { private static final ResubmitLock INSTANCE = new ResubmitLock; } public static ResubmitLock getInstance { return SingletonInstance.INSTANCE; } public static String handleKey(String param) { return DigestUtils.md5Hex(param == ? \"大众\"大众 : param); } / 加锁 putIfAbsent 是原子操作担保线程安全 @param key 对应的key @param value @return / public boolean lock(final String key, Object value) { return Objects.is(LOCK_CACHE.putIfAbsent(key, value)); } / 延时开释锁 用以掌握短韶光内的重复提交 @param lock 是否须要解锁 @param key 对应的key @param delaySeconds 延时时间 / public void unLock(final boolean lock, final String key, final int delaySeconds) { if (lock) { EXECUTOR.schedule( -> { LOCK_CACHE.remove(key); }, delaySeconds, TimeUnit.SECONDS); } }}

@Log4j@Aspect@Componentpublic class ResubmitDataAspect { private final static String DATA = \"大众data\"大众; private final static Object PRESENT = new Object; @Around(\"大众@annotation(com.cn.xxx.common.annotation.Resubmit)\"大众) public Object handleResubmit(ProceedingJoinPoint joinPoint) throws Throwable { Method method = ((MethodSignature) joinPoint.getSignature).getMethod; //获取表明信息 Resubmit annotation = method.getAnnotation(Resubmit.class); int delaySeconds = annotation.delaySeconds; Object pointArgs = joinPoint.getArgs; String key = \"大众\"大众; //获取第一个参数 Object firstParam = pointArgs[0]; if (firstParam instanceof RequestDTO) { //解析参数 JSONObject requestDTO = JSONObject.parseObject(firstParam.toString); JSONObject data = JSONObject.parseObject(requestDTO.getString(DATA)); if (data != ) { StringBuffer sb = new StringBuffer; data.forEach((k, v) -> { sb.append(v); }); //天生加密参数 利用了content_MD5的加密办法 key = ResubmitLock.handleKey(sb.toString); } } //实行锁 boolean lock = false; try { //设置解锁key lock = ResubmitLock.getInstance.lock(key, PRESENT); if (lock) { //放行 return joinPoint.proceed; } else { //相应重复提交非常 return new ResponseDTO<>(ResponseCode.REPEAT_SUBMIT_OPERATION_EXCEPTION); } } finally { //设置解锁key和解锁韶光 ResubmitLock.getInstance.unLock(lock, key, delaySeconds); } }}

@ApiOperation(value = \"大众保存我的帖子接口\"大众, notes = \公众保存我的帖子接口\"大众)@PostMapping(\"大众/posts/save\"大众)@Resubmit(delaySeconds = 10)public ResponseDTO saveBbsPosts(@RequestBody @Validated RequestDTO requestDto) { return bbsPostsBizService.saveBbsPosts(requestDto);}

以上便是本地锁的办法进行的幂等提交 利用了Content-MD5 进行加密 只要参数不变,参数加密 密值不变,key存在就阻挡提交

当然也可以利用 一些其他署名校验 在某一次提交时先 天生固定署名 提交到后端 根据后端解析统一的署名作为 每次提交的验证token 去缓存中处理即可.

8、借助分布式redis锁 （参考其他）

在 pom.xml 中添加上 starter-web、starter-aop、starter-data-redis 的依赖即可

<dependencies> <dependency> <groupId>org.springframework.bootgroupId> <artifactId>spring-boot-starter-webartifactId> dependency> <dependency> <groupId>org.springframework.bootgroupId> <artifactId>spring-boot-starter-aopartifactId> dependency> <dependency> <groupId>org.springframework.bootgroupId> <artifactId>spring-boot-starter-data-redisartifactId> dependency>dependencies>

属性配置 在 application.properites 资源文件中添加 redis 干系的配置项

spring.redis.host=localhostspring.redis.port=6379spring.redis.password=123456

紧张实现办法:

熟习 Redis 的朋友都知道它是线程安全的，我们利用它的特性可以很轻松的实现一个分布式锁，如 opsForValue.setIfAbsent(key,value)

它的浸染便是如果缓存中没有当前 Key 则进行缓存同时返回 true 反之亦然；

当缓存后给 key 在设置个过期韶光，防止由于系统崩溃而导致锁迟迟不开释形成去世锁；

那么我们是不是可以这样认为当返回 true 我们认为它获取到锁了，在锁未开释的时候我们进行非常的抛出…

@Aspect@Configurationpublic class LockMethodInterceptor { @Autowired public LockMethodInterceptor(RedisLockHelper redisLockHelper, CacheKeyGenerator cacheKeyGenerator) { this.redisLockHelper = redisLockHelper; this.cacheKeyGenerator = cacheKeyGenerator; } private final RedisLockHelper redisLockHelper; private final CacheKeyGenerator cacheKeyGenerator; @Around(\"大众execution(public (..)) && @annotation(com.battcn.annotation.CacheLock)\"大众) public Object interceptor(ProceedingJoinPoint pjp) { MethodSignature signature = (MethodSignature) pjp.getSignature; Method method = signature.getMethod; CacheLock lock = method.getAnnotation(CacheLock.class); if (StringUtils.isEmpty(lock.prefix)) { throw new RuntimeException(\"大众lock key don't ...\"大众); } final String lockKey = cacheKeyGenerator.getLockKey(pjp); String value = UUID.randomUUID.toString; try { // 假设上锁成功，但是设置过期韶光失落效，往后拿到的都是 false final boolean success = redisLockHelper.lock(lockKey, value, lock.expire, lock.timeUnit); if (!success) { throw new RuntimeException(\"大众重复提交\公众); } try { return pjp.proceed; } catch (Throwable throwable) { throw new RuntimeException(\"大众系统非常\公众); } } finally { // TODO 如果演示的话须要注释该代码;实际该当放开 redisLockHelper.unlock(lockKey, value); } }}

RedisLockHelper 通过封装成 API 办法调用，灵巧度更加高

@Configuration@AutoConfigureAfter(RedisAutoConfiguration.class)public class RedisLockHelper { private static final String DELIMITER = \"大众|\"大众; / 如果哀求比较高可以通过注入的办法分配 / private static final ScheduledExecutorService EXECUTOR_SERVICE = Executors.newScheduledThreadPool(10); private final StringRedisTemplate stringRedisTemplate; public RedisLockHelper(StringRedisTemplate stringRedisTemplate) { this.stringRedisTemplate = stringRedisTemplate; } / 获取锁（存在去世锁风险） @param lockKey lockKey @param value value @param time 超时时间 @param unit 过期单位 @return true or false / public boolean tryLock(final String lockKey, final String value, final long time, final TimeUnit unit) { return stringRedisTemplate.execute((RedisCallback<Boolean>) connection -> connection.set(lockKey.getBytes, value.getBytes, Expiration.from(time, unit), RedisStringCommands.SetOption.SET_IF_ABSENT)); } / 获取锁 @param lockKey lockKey @param uuid UUID @param timeout 超时时间 @param unit 过期单位 @return true or false / public boolean lock(String lockKey, final String uuid, long timeout, final TimeUnit unit) { final long milliseconds = Expiration.from(timeout, unit).getExpirationTimeInMilliseconds; boolean success = stringRedisTemplate.opsForValue.setIfAbsent(lockKey, (System.currentTimeMillis + milliseconds) + DELIMITER + uuid); if (success) { stringRedisTemplate.expire(lockKey, timeout, TimeUnit.SECONDS); } else { String oldVal = stringRedisTemplate.opsForValue.getAndSet(lockKey, (System.currentTimeMillis + milliseconds) + DELIMITER + uuid); final String oldValues = oldVal.split(Pattern.quote(DELIMITER)); if (Long.parseLong(oldValues[0]) + 1 <= System.currentTimeMillis) { return true; } } return success; } / @see Redis Documentation: SET / public void unlock(String lockKey, String value) { unlock(lockKey, value, 0, TimeUnit.MILLISECONDS); } / 延迟unlock @param lockKey key @param uuid client(最好是唯一键的) @param delayTime 延迟韶光 @param unit 韶光单位 / public void unlock(final String lockKey, final String uuid, long delayTime, TimeUnit unit) { if (StringUtils.isEmpty(lockKey)) { return; } if (delayTime <= 0) { doUnlock(lockKey, uuid); } else { EXECUTOR_SERVICE.schedule( -> doUnlock(lockKey, uuid), delayTime, unit); } } / @param lockKey key @param uuid client(最好是唯一键的) / private void doUnlock(final String lockKey, final String uuid) { String val = stringRedisTemplate.opsForValue.get(lockKey); final String values = val.split(Pattern.quote(DELIMITER)); if (values.length <= 0) { return; } if (uuid.equals(values[1])) { stringRedisTemplate.delete(lockKey); } }}

redis的提交参照

https://blog.battcn.com/2018/06/13/springboot/v2-cache-redislock/