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基于?Spring?Aop?環繞通知實現?Redis?緩存雙刪功能(示例代碼)_Redis

作者：風起風落丶 ? 更新時間： 2022-10-10 編程語言

基于 spring aop 常規應用場景多是用于日志記錄以及實現 redis 分布式鎖，在 github 中也有項目是把它拿來當作緩存的異常捕捉。從而避免影響實際業務的開發；在某天，筆者有個業務開發是給某個服務模塊增加 redis 緩存。增加緩存就會涉及 redis 刪除。所以筆者就在思考是不是可以用環繞通知的方式來進行實現

代碼實現

結構示意圖：

自定義注解 RedisDelByDbUpdate

@Repeatable 表示允許在同一個地方上使用相同的注解，沒有該注解時貼相同注解會報錯

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(RedisDelByDbUpdateList.class)
public @interface RedisDelByDbUpdate {
    /**
     * 具體操作得緩存前綴
     */
    String redisPrefix() default "";
 
    /**
     * 具體的緩存名稱，為空則刪除 redisPrefix 下的所有緩存
     */
    String fieldName() default "";
}

自定義注解 RedisDelByUpdateList

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

具體實現 redis 雙刪邏輯

@Aspect
@Component
@Slf4j
public class RedisDelAspect_bak {
    //環繞增強
    @Autowired
    private RedisUtil redis;
 
    @Pointcut("@annotation(com.cili.baseserver.aop.annotation.RedisDelByDbUpdate) " +
            "|| @annotation(com.cili.baseserver.aop.annotation.RedisDelByDbUpdateList)")
    public void pointCut() {
 
    }
 
    // 線程池定長設置：最佳線程數目 = ((線程等待時間+線程CPU時間)/線程CPU時間 )* CPU數目
    ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(26);
 
    /**
     * 環繞增強
     *
     * @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緩存前綴不能為空");
            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 {
            // 獲取所有該前綴下緩存
            Set<String> keys = redis.keys(prefix + "*");
            redisKeys = keys.stream().toArray(String[]::new);
        }
 
        // 刪除緩存
        String redisKey = prefix + key;
        delete(redisKey, redisKeys);
        Object result = object.callback();
 
        // 延時刪除
        try {
            String[] finalRedisKeys = redisKeys;
            threadPool.schedule(new Runnable() {
                @Override
                public void run() {
                    delete(redisKey, finalRedisKeys);
                }
            }, 500, TimeUnit.MILLISECONDS);
        } catch (Exception e) {
            log.error("線程池延時刪除緩存失敗:{}", 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 不能為空");
            throw new BizException(BaseResponseCode.PARAM_IS_NOT_NULL);
        }
        try {
            bannerMapper.batchDeleted(ids);
        } catch (Exception e) {
            log.error("==>批量刪除Banner錯誤:{}<==", e);
            throw new BizException(BaseResponseCode.SYSTEM_BUSY);
        }
    }
}

原文鏈接：https://blog.csdn.net/java_best_LJF/article/details/118327818

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