@CacheEvict注解失效的经历及解决方法是什么
@CacheEvict注解失效的经历及解决方法是什么，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
排查@CacheEvict注解失效
我简单看了一下《Spring实战》中的demo，然后就应用到业务代码中了，本以为如此简单的事情，竟然在代码提交后的1个周，被同事发现。selectByTaskId()方法查出来的数据总是过时的。
代码如下：
@Cacheable("taskParamsCache")List selectByTaskId(Long taskId);// ...// ...@CacheEvict("taskParamsCache")int deleteByTaskId(Long taskId); 想要的效果是当程序调用selectByTaskId()方法时，把结果缓存下来，然后在调用deleteByTaskId()方法时，将缓存清空。
经过数据库数据对比之后，把问题排查的方向定位在@CacheEvict注解失效了。
下面是我通过源码跟踪排查问题的过程
在deleteByTaskId()方法的调用出打断点，跟进代码到spring生成的代理层。
@Override @Nullable public Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable { Object oldProxy = null; boolean setProxyContext = false; Object target = null; TargetSource targetSource = this.advised.getTargetSource(); try { if (this.advised.exposeProxy) { // Make invocation available if necessary. oldProxy = AopContext.setCurrentProxy(proxy); setProxyContext = true; } // Get as late as possible to minimize the time we "own" the target, in case it comes from a pool... target = targetSource.getTarget(); Class targetClass = (target != null ? target.getClass() : null); List通过getInterceptorsAndDynamicInterceptionAdvice获取到当前方法的拦截器，里面包含了CacheIneterceptor，说明注解被spring检测到了。
进入CglibMethodInvocation(proxy, target, method, args, targetClass, chain, methodProxy).proceed()方法内部
org.springframework.aop.framework.ReflectiveMethodInvocation#proceed
@Override @Nullable public Object proceed() throws Throwable { // We start with an index of -1 and increment early. if (this.currentInterceptorIndex == this.interceptorsAndDynamicMethodMatchers.size() - 1) { return invokeJoinpoint(); } Object interceptorOrInterceptionAdvice = this.interceptorsAndDynamicMethodMatchers.get(++this.currentInterceptorIndex); if (interceptorOrInterceptionAdvice instanceof InterceptorAndDynamicMethodMatcher) { // Evaluate dynamic method matcher here: static part will already have // been evaluated and found to match. InterceptorAndDynamicMethodMatcher dm = (InterceptorAndDynamicMethodMatcher) interceptorOrInterceptionAdvice; if (dm.methodMatcher.matches(this.method, this.targetClass, this.arguments)) { return dm.interceptor.invoke(this); } else { // Dynamic matching failed. // Skip this interceptor and invoke the next in the chain. return proceed(); } } else { // It's an interceptor, so we just invoke it: The pointcut will have // been evaluated statically before this object was constructed. return ((MethodInterceptor) interceptorOrInterceptionAdvice).invoke(this); } }this.interceptorsAndDynamicMethodMatchers.get(++this.currentInterceptorIndex)方法取第一个拦截器，正是我们要关注的CacheIneterceptor，然后调用((MethodInterceptor) interceptorOrInterceptionAdvice).invoke(this)方法，继续跟进
org.springframework.cache.interceptor.CacheInterceptor#invoke
@Override @Nullable public Object invoke(final MethodInvocation invocation) throws Throwable { Method method = invocation.getMethod(); CacheOperationInvoker aopAllianceInvoker = () -> { try { return invocation.proceed(); } catch (Throwable ex) { throw new CacheOperationInvoker.ThrowableWrapper(ex); } }; try { return execute(aopAllianceInvoker, invocation.getThis(), method, invocation.getArguments()); } catch (CacheOperationInvoker.ThrowableWrapper th) { throw th.getOriginal(); } }进入execute方法
protected Object execute(CacheOperationInvoker invoker, Object target, Method method, Object[] args) { // Check whether aspect is enabled (to cope with cases where the AJ is pulled in automatically) if (this.initialized) { Class targetClass = getTargetClass(target); CacheOperationSource cacheOperationSource = getCacheOperationSource(); if (cacheOperationSource != null) { Collection operations = cacheOperationSource.getCacheOperations(method, targetClass); if (!CollectionUtils.isEmpty(operations)) { return execute(invoker, method, new CacheOperationContexts(operations, method, args, target, targetClass)); } } } return invoker.invoke(); } cacheOperationSource记录系统中所有使用了缓存的方法，cacheOperationSource.getCacheOperations(method, targetClass)能获取deleteByTaskId()方法缓存元数据，然后执行execute()方法
@Nullable private Object execute(final CacheOperationInvoker invoker, Method method, CacheOperationContexts contexts) { // Special handling of synchronized invocation if (contexts.isSynchronized()) { CacheOperationContext context = contexts.get(CacheableOperation.class).iterator().next(); if (isConditionPassing(context, CacheOperationExpressionEvaluator.NO_RESULT)) { Object key = generateKey(context, CacheOperationExpressionEvaluator.NO_RESULT); Cache cache = context.getCaches().iterator().next(); try { return wrapCacheValue(method, cache.get(key, () -> unwrapReturnValue(invokeOperation(invoker)))); } catch (Cache.ValueRetrievalException ex) { // The invoker wraps any Throwable in a ThrowableWrapper instance so we // can just make sure that one bubbles up the stack. throw (CacheOperationInvoker.ThrowableWrapper) ex.getCause(); } } else { // No caching required, only call the underlying method return invokeOperation(invoker); } } // Process any early evictions processCacheEvicts(contexts.get(CacheEvictOperation.class), true, CacheOperationExpressionEvaluator.NO_RESULT); // Check if we have a cached item matching the conditions Cache.ValueWrapper cacheHit = findCachedItem(contexts.get(CacheableOperation.class)); // Collect puts from any @Cacheable miss, if no cached item is found List cachePutRequests = new LinkedList<>(); if (cacheHit == null) { collectPutRequests(contexts.get(CacheableOperation.class), CacheOperationExpressionEvaluator.NO_RESULT, cachePutRequests); } Object cacheValue; Object returnValue; if (cacheHit != null && cachePutRequests.isEmpty() && !hasCachePut(contexts)) { // If there are no put requests, just use the cache hit cacheValue = cacheHit.get(); returnValue = wrapCacheValue(method, cacheValue); } else { // Invoke the method if we don't have a cache hit returnValue = invokeOperation(invoker); cacheValue = unwrapReturnValue(returnValue); } // Collect any explicit @CachePuts collectPutRequests(contexts.get(CachePutOperation.class), cacheValue, cachePutRequests); // Process any collected put requests, either from @CachePut or a @Cacheable miss for (CachePutRequest cachePutRequest : cachePutRequests) { cachePutRequest.apply(cacheValue); } // Process any late evictions processCacheEvicts(contexts.get(CacheEvictOperation.class), false, cacheValue); return returnValue; } 这里大致过程是：
先执行beforInvokeEvict ---- 执行数据库delete操作 --- 执行CachePut操作 ---- 执行afterInvokeEvict
我们的注解是方法调用后再使缓存失效，直接所以有效的操作应在倒数第2行
private void performCacheEvict( CacheOperationContext context, CacheEvictOperation operation, @Nullable Object result) { Object key = null; for (Cache cache : context.getCaches()) { if (operation.isCacheWide()) { logInvalidating(context, operation, null); doClear(cache); } else { if (key == null) { key = generateKey(context, result); } logInvalidating(context, operation, key); doEvict(cache, key); } } }这里通过context.getCaches()获取到name为taskParamsCache的缓存
然后generateKey生成key，注意这里，发现生成的key是com.xxx.xxx.atomic.impl.xxxxdeleteByTaskId982，但是缓存中的key却是com.xxx.xxx.atomic.impl.xxxxselectByTaskId982，下面调用的doEvict(cache, key)方法不再跟进了，就是从cache中移除key对应值。明显这里key对应不上的，这也是导致@CacheEvict没有生效的原因。
小结一下
我还是太大意了，当时看了注解@CacheEvict的对key的注释：
大意就是如果没有指定key，那就会使用方法所有参数生成一个key，明显com.xxx.xxx.atomic.impl.xxxxselectByTaskId982是方法名 + 参数，可是你没说把方法名还加上了啊，说好的只用参数呢，哈哈，这个bug是我使用不当引出的，很多人不会犯这种低级错误。
解决办法就是使用SpEL明确定义key
@Cacheable(value = "taskParamsCache", key = "#taskId")ListselectByTaskId(Long taskId);// ...// ...@CacheEvict(value = "taskParamsCache", key = "#taskId")int deleteByTaskId(Long taskId);
说说spring全家桶中@CacheEvict无效情况
@CacheEvict(value ="test", allEntries = true）
1、使用@CacheEvict注解的方法必须是controller层直接调用，service里间接调用不生效。
2、原因是因为key值跟你查询方法的key值不统一，所以导致缓存并没有清除
3、把@CacheEvict的方法和@Cache的方法放到一个java文件中写，他俩在两个java文件的话，会导致@CacheEvict失效。
4、返回值必须设置为void
@CacheEvict annotation
It is important to note that void methods can be used with @CacheEvict
5、@CacheEvict必须作用在走代理的方法上
在使用Spring @CacheEvict注解的时候，要注意，如果类A的方法f1()被标注了 @CacheEvict注解，那么当类A的其他方法，例如：f2()，去直接调用f1()的时候， @CacheEvict是不起作用的，原因是 @CacheEvict是基于Spring AOP代理类，f2()属于内部方法，直接调用f1()时，是不走代理的。
举个例子
不生效：
@Overridepublic void saveEntity(Menu menu) { try { mapper.insert(menu); //Cacheable 不生效 this.test(); }catch(Exception e){ e.printStackTrace(); }}@CacheEvict(value = "test" , allEntries = true)public void test() {}正确使用：
@Override@CacheEvict(value = "test" , allEntries = true)public void saveEntity(Menu menu) { try { mapper.insert(menu); }catch(Exception e){ e.printStackTrace(); }}看完上述内容是否对您有帮助呢？如果还想对相关知识有进一步的了解或阅读更多相关文章，请关注行业资讯频道，感谢您对的支持。
