使用EHCache在Terracotta配置中定位Hibernate会话工厂时出错

Question

任何人都可以帮助我为什么下面的错误消息会出现在应用程序服务器上。我正在尝试用Terracotta设置EHCache。请建议任何线索，为什么会出现此消息。

[DEBUG][08/05/12 13:50:19.648][CacheByAmitNode8081] Running mbean initializer task for ehcache hibernate...
[DEBUG][08/05/12 13:50:19.766][CacheByAmitNode8081] Successfully registered bean
[ERROR][08/05/12 13:50:19.805][CacheByAmitNode8081] Error locating Hibernate Session Factory
java.lang.NullPointerException
    at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:36)
    at sun.reflect.UnsafeQualifiedObjectFieldAccessorImpl.get(UnsafeQualifiedObjectFieldAccessorImpl.java:20)
    at java.lang.reflect.Field.get(Field.java:358)
    at org.hibernate.cache.ehcache.management.impl.ProviderMBeanRegistrationHelper$RegisterMBeansTask.locateSessionFactory(ProviderMBeanRegistrationHelper.java:152)
    at org.hibernate.cache.ehcache.management.impl.ProviderMBeanRegistrationHelper$RegisterMBeansTask.run(ProviderMBeanRegistrationHelper.java:117)
    at java.util.TimerThread.mainLoop(Timer.java:512)
    at java.util.TimerThread.run(Timer.java:462)
[DEBUG][08/05/12 13:50:19.815][CacheByAmitNode8081] SessionFactory is probably still being initialized... waiting for it to complete before enabling hibernate statistics monitoring via JMX

Answer 1

我今天遇到了同样的问题。这似乎是由类 ProviderMBeanRegistrationHelper 在第 152 行中的一个错误引起的

Map map = (Map) instancesField.get( null );

在第146和147行

Class factoryType = SessionFactoryRegistry.class;
Field instancesField = getField( factoryType, "sessionFactoryMap" );

所以我们知道instanceField是来自类SessionFactory注册表实例的字段，它恰好有一个可以从类中静态获取的实例

SessionFactoryRegistry.INSTANCE

总之，我修改了第152行，如下所示

Map map = (Map) instancesField.get( SessionFactoryRegistry.INSTANCE );

编译并替换了hibernate-ehcache jar文件中的类，异常消失了。我将提出一个有关此的问题。