基于 Spring Aop 环绕通知实现 Redis 缓存双删功能(示例代码)

基于 spring aop 常规应用场景多是用于日志记录以及实现 redis 分布式锁,在 github 中也有项目是把它拿来当作缓存的异常捕捉。从而避免影响实际业务的开发;在某天,笔者有个业务开发是给某个服务模块增加 redis 缓存。增加缓存就会涉及 redis 删除。所以笔者就在思考是不是可以用环绕通知的方式来进行实现

代码实现

结构示意图:

自定义注解 RedisDelByDbUpdate

@Repeatable 表示允许在同一个地方上使用相同的注解,没有该注解时贴相同注解会报错

@Target(ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME) @Documented @Repeatable(RedisDelByDbUpdateList.class) public @interface RedisDelByDbUpdate { /** * 具体操作得缓存前缀 */ String redisPrefix() default ""; /** * 具体的缓存名称,为空则删除 redisPrefix 下的所有缓存 */ String fieldName() default ""; }

自定义注解 RedisDelByUpdateList

@Target(ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface RedisDelByDbUpdateList { RedisDelByDbUpdate[] value(); }

具体实现 redis 双删逻辑

@Aspect @Component @Slf4j public class RedisDelAspect_bak { //环绕增强 @Autowired private RedisUtil redis; @Pointcut("@annotation(com.cili.baseserver.aop.annotation.RedisDelByDbUpdate) " + "|| @annotation(com.cili.baseserver.aop.annotation.RedisDelByDbUpdateList)") public void pointCut() { } // 线程池定长设置:最佳线程数目 = ((线程等待时间+线程CPU时间)/线程CPU时间 )* CPU数目 ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(26); /** * 环绕增强 * * @param point * @return * @throws Throwable */ @Around("pointCut()") public Object around(ProceedingJoinPoint point) throws Throwable { MethodSignature signature = (MethodSignature) point.getSignature(); Method method = signature.getMethod(); RedisDelByDbUpdate redisDelByDbUpdate = method.getAnnotation(RedisDelByDbUpdate.class); if (redisDelByDbUpdate != null) { return singleRedisDel(redisDelByDbUpdate, point); } RedisDelByDbUpdateList updateList = method.getAnnotation(RedisDelByDbUpdateList.class); return arraysRedisDel(updateList, point); } private Object singleRedisDel(RedisDelByDbUpdate redisDelByDbUpdate, ProceedingJoinPoint point) throws Throwable { return handle(redisDelByDbUpdate, point, new IObjectCallback<Object>() { public <T> T callback() throws Throwable { return (T) point.proceed(); } }); } private Object arraysRedisDel(RedisDelByDbUpdateList updateList, ProceedingJoinPoint point) throws Throwable { RedisDelByDbUpdate[] redisDelByDbUpdates = updateList.value(); for (int i = 0; i < redisDelByDbUpdates.length; i++) { boolean flag = i == redisDelByDbUpdates.length - 1 ? true : false; Object obj = handle(redisDelByDbUpdates[i], point, new IObjectCallback<Object>() { public <T> T callback() throws Throwable { return flag ? (T) point.proceed() : null; } }); if (flag) return obj; } return null; } private Object handle(RedisDelByDbUpdate redisDelByDbUpdate, ProceedingJoinPoint point, IObjectCallback<Object> object) throws Throwable { String prefix = redisDelByDbUpdate.redisPrefix(); String fieldName = redisDelByDbUpdate.fieldName(); if (ValueUtil.isEmpty(prefix)) { log.info("redis缓存前缀不能为空"); throw new BizException(BaseResponseCode.SYSTEM_BUSY); } Object arg = point.getArgs()[0]; String key = ""; String[] redisKeys = null; if (ValueUtil.isNotEmpty(fieldName)) { if (arg instanceof ArrayList) { redisKeys = ((ArrayList<?>) arg).stream().map(item -> prefix + item).toArray(String[]::new); } else { Map<String, Object> map = (Map<String, Object>) JsonUtil.toMap(JsonUtil.toJSON(point.getArgs()[0])); key = map.get(fieldName).toString(); } } else { // 获取所有该前缀下缓存 Set<String> keys = redis.keys(prefix + "*"); redisKeys = keys.stream().toArray(String[]::new); } // 删除缓存 String redisKey = prefix + key; delete(redisKey, redisKeys); Object result = object.callback(); // 延时删除 try { String[] finalRedisKeys = redisKeys; threadPool.schedule(new Runnable() { @Override public void run() { delete(redisKey, finalRedisKeys); } }, 500, TimeUnit.MILLISECONDS); } catch (Exception e) { log.error("线程池延时删除缓存失败:{}", redisKey); } return result; } private void delete(String redisKey, String[] redisKeys) { if (ValueUtil.isEmpty(redisKeys)) { redis.delete(redisKey); return; } redis.del(redisKeys); } }

注解使用示例

public class Test { @Override @RedisDelByDbUpdate(redisPrefix = RedisConstant.BANNER, fieldName = "ids") @RedisDelByDbUpdate(redisPrefix = RedisConstant.BANNER_LIST) public void batchDeleted(List<String> ids) throws BizException { if (CollectionUtils.isEmpty(ids)) { log.info("banner ID 不能为空"); throw new BizException(BaseResponseCode.PARAM_IS_NOT_NULL); } try { bannerMapper.batchDeleted(ids); } catch (Exception e) { log.error("==>批量删除Banner错误:{}<==", e); throw new BizException(BaseResponseCode.SYSTEM_BUSY); } } }

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