Hibernate + EhCache = java.io.NotSerializableException

Question

我正在做负载测试。大约900个请求后，我得到这个错误：

[ 03.08.10 11:49:00.465] [Store org.hibernate.cache.StandardQueryCache Spool Thread] ERROR net.sf.ehcache.store.DiskStore - org.hibernate.cache.StandardQueryCacheCache: Failed to write element to disk 'sql: select hotelfeatu0_.name as col_0_0_ from feature hotelfeatu0_ where hotelfeatu0_.class='org.company.domains.HotelFeatures' and hotelfeatu0_.lang=? and hotelfeatu0_.hotel_id=?; parameters: ; named parameters: {ht=100: 'Hotel', lng=en}'. Initial cause was org.company.domains.Hotel 
java.io.NotSerializableException: org.company.domains.Hotel 
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1156) 
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509) 
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474) 
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392) 
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150) 
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326) 
    at java.util.HashMap.writeObject(HashMap.java:1001) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:945) 
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1461) 
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392) 
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150) 
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509) 
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474) 
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392) 
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150) 
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509) 
    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:416) 
    at net.sf.ehcache.Element.writeObject(Element.java:729) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:945) 
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1461) 
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392) 
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150) 
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326) 
    at net.sf.ehcache.util.MemoryEfficientByteArrayOutputStream.serialize(MemoryEfficientByteArrayOutputStream.java:75) 
    at net.sf.ehcache.store.DiskStore.serializeElement(DiskStore.java:781) 
    at net.sf.ehcache.store.DiskStore.writeElement(DiskStore.java:735) 
    at net.sf.ehcache.store.DiskStore.writeOrReplaceEntry(DiskStore.java:729) 
    at net.sf.ehcache.store.DiskStore.flushSpool(DiskStore.java:703) 
    at net.sf.ehcache.store.DiskStore.throwableSafeFlushSpoolIfRequired(DiskStore.java:671) 
    at net.sf.ehcache.store.DiskStore.spoolAndExpiryThreadMain(DiskStore.java:640) 
    at net.sf.ehcache.store.DiskStore.access$900(DiskStore.java:68) 
    at net.sf.ehcache.store.DiskStore$SpoolAndExpiryThread.run(DiskStore.java:1110) 

这里是我的ehcache.xml中：

<?xml version="1.0" encoding="UTF-8"?> 
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="ehcache.xsd" updateCheck="false"> 

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

    <defaultCache 
      maxElementsInMemory="10000" 
      eternal="false" 
      timeToIdleSeconds="120" 
      timeToLiveSeconds="120" 
      overflowToDisk="true" 
      maxElementsOnDisk="10000000" 
      diskPersistent="false" 
      diskExpiryThreadIntervalSeconds="120" 
      memoryStoreEvictionPolicy="LRU" 
    /> 

    <cache 
       name="org.hibernate.cache.StandardQueryCache" 
       maxElementsInMemory="5" 
       eternal="false" 
       timeToLiveSeconds="120" 
       overflowToDisk="true" 
    /> 

</ehcache> 

Hibernate的配置：

hibernate { 
    cache.use_second_level_cache=true 
    cache.use_query_cache=true 
    cache.provider_class='org.hibernate.cache.EhCacheProvider' 
    connection.useUnicode=true 
    connection.characterEncoding='UTF-8' 
    dialect = 'org.hibernate.dialect.MySQL5InnoDBDialect' 
} 

Answer 1

日志告诉我，出现这种情况，因为查询缓存尝试在磁盘上写入您的org.company.domains.Hotel对象之一。毫不奇怪，在负载测试期间可能会发生这种情况，因为在尝试将其刷新到磁盘之前，只允许查询缓存中的5个元素存储在内存中。

您或者需要为查询缓存设置org.company.domains.Hotel执行java.io.Serializable或设置overflowToDisk="false"。