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我正在使用 Ehcache 来缓存在我的应用程序中加载非常昂贵的对象。在启动时，我缓存了所有需要的对象，并且它们每天通过一个单独的进程刷新一次。

但是，似乎在我将对象添加到缓存后不久，它们就消失了。没有报告被驱逐，但由于某种原因，这些对象没有在缓存中持久存在。当我运行 ObjectLoader.loadCache() 这是我收到的输出：

2012-09-01 17:25:37,121 [main] DEBUG ObjectLoader.getObject():65 - ************************************
2012-09-01 17:25:37,121 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 0
2012-09-01 17:25:37,121 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 501
2012-09-01 17:26:17,271 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1
2012-09-01 17:26:17,271 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0
2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 501
2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():65 - ************************************
2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1
2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 518
2012-09-01 17:26:35,894 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1
2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0
2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 518
2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():65 - ************************************
2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1
2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 516
2012-09-01 17:27:31,997 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1
2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0
2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 516
2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():65 - ************************************
2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1
2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 515
2012-09-01 17:28:20,343 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1
2012-09-01 17:28:20,343 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0
2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 515
2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():65 - ************************************
2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1
2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 525
2012-09-01 17:29:05,616 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1
2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0
2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 525
2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():65 - ************************************
2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1
2012-09-01 17:29:05,618 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 512
2012-09-01 17:29:38,790 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1
2012-09-01 17:29:38,790 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0
2012-09-01 17:29:38,790 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 512

是我的 ehcache 配置错误还是我的代码中有错误？任何帮助，将不胜感激。谢谢。

我正在使用 spring 3.1.0、ehcache-spring-annotations 1.1.2 和 ehcache 2.4.2

ObjectCacheFacade.java

@Component()
public class ObjectCacheFacade {
    private static final String CACHE_KEY = "myObjectCache";

    @Resource
    private CacheManager cacheManager;
    private Cache cache;

    public ObjectCacheFacade() {
        cacheManager = CacheManager.getInstance();
        this.cache = cacheManager.getCache(CACHE_KEY);
    }

    public Object getObjectFromCache(String objectId) {
        Object result = null;
        Element element = cache.get(objectId);

        if (element != null && element.getValue() != null) {
            result = element.getObjectValue();
        } 

        return result;
    }

    public void putObjectIntoCache(String objectId, Object object) {
        Element element = new Element(objectId, object);
        cache.put(element);
    }

    public int getSize() {
        return cache.getSize();
    }

    public void removeObjectFromCache(String objectId) {
        cache.remove(objectId);
    }

    public void flushCache() {
        cache.removeAll();
    }

    public Cache getCache() {
        return cache;
    }
}

对象加载器.java

@Service
public class ObjectLoader {
    private static final Logger log = Logger.getLogger(ObjectLoader.class);

    @Resource
    protected ObjectDao objectDao;
    @Resource
    protected ObjectCacheFacade objectCache;

    public void loadCache() {
        List<String> objectIds = objectDao.getObjectIds();

        for (String objectId : objectIds) {
            loadObject(objectId);
        }
    }

    public Object getObject(String objectId) {
        log.debug("************************************");
        log.debug("Number of objects in cache: " + objectCache.getSize());

        Object object = objectCache.getObjectFromCache(objectId);

        if (object == null) {
            log.debug("Object not in cache | " + objectId);
            object = objectDao.getObject(objectId);

            if (object != null) {
                objectCache.putObjectIntoCache(objectId, object);

                log.debug("Number of objects in cache: " + objectCache.getSize());
                log.debug("Number of objects evicted from cache: " + objectCache.getCache().getCacheEventNotificationService().getElementsEvictedCounter());
                for (Object key : objectCache.getCache().getKeys()) {
                    log.debug("Object key found: " + key);
                }
            } 
        } 

        return object;
    }
}

ehcache.xml

<ehcache>
    <diskStore path="java.io.tmpdir"/>

    <defaultCache
        maxElementsInMemory="1000"
        eternal="false"
        timeToIdleSeconds="60"
        timeToLiveSeconds="300"
        overflowToDisk="false"
        memoryStoreEvictionPolicy="LRU"
       />

    <cache
        name="myObjectCache"
        maxElementsInMemory="1000"
        eternal="true"
        timeToIdleSeconds="0"
        timeToLiveSeconds="0"
        overflowToDisk="false"
        diskPersistent="true"
        memoryStoreEvictionPolicy="LRU"
       />

</ehcache>

应用程序上下文.xml

<bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean" />
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1 回答 1

6

由于diskPersistent设置为 trueEhcache是在将对象添加到缓存后尝试将其写入磁盘。但是，主缓存对象中的一个嵌套对象没有实现Serializable，因此它在磁盘写入时引发异常，然后将对象从缓存中逐出。此驱逐未显示在缓存统计信息中，因为它没有被memoryStoreEvictionPolicy.

这应该是一个很容易找到的错误，但是该项目不包含该slf4j-log4j12库，因此异常被吞没而不是被写入日志。一旦日志处理得当，问题出在哪里就很明显了。

哦，好吧，生活和学习，我猜...

于 2012-09-02T11:54:06.507 回答