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
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);
}
}
}
