DeferredFileOutputStream抛出NotSerializableException

[xiao_cs]

搜索过类似异常的帖子，但终究为找到最终解决方案。
背景描述: java web project.
使用struts1.2做文件上传之后，tomcat(apache-tomcat-6.0.18)会抛出如下异常

2011-12-12 14:34:05 org.apache.catalina.session.StandardSession writeObject
警告: Cannot serialize session attribute fileForm for session 7B0AFF2DF65AC74308BDBC77AB5AF92A
java.io.NotSerializableException: org.apache.commons.fileupload.DeferredFileOutputStream
	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.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.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 org.apache.catalina.session.StandardSession.writeObject(StandardSession.java:1517)
	at org.apache.catalina.session.StandardSession.writeObjectData(StandardSession.java:959)
	at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:517)
	at org.apache.catalina.session.StandardManager.unload(StandardManager.java:463)
	at org.apache.catalina.session.StandardManager.stop(StandardManager.java:667)
	at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4519)
	at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3093)
	at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:404)
	at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1309)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
	at java.lang.Thread.run(Thread.java:619)
2011-12-12 14:34:06 org.apache.catalina.session.StandardManager doLoad
严重: IOException while loading persisted sessions: java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: org.apache.commons.fileupload.DeferredFileOutputStream
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: org.apache.commons.fileupload.DeferredFileOutputStream
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1333)
	at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
	at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
	at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
	at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
	at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
	at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
	at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
	at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
	at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
	at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
	at org.apache.catalina.session.StandardSession.readObject(StandardSession.java:1441)
	at org.apache.catalina.session.StandardSession.readObjectData(StandardSession.java:942)
	at org.apache.catalina.session.StandardManager.doLoad(StandardManager.java:394)
	at org.apache.catalina.session.StandardManager.load(StandardManager.java:321)
	at org.apache.catalina.session.StandardManager.start(StandardManager.java:637)
	at org.apache.catalina.core.StandardContext.start(StandardContext.java:4351)
	at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3099)
	at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:404)
	at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1309)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
	at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.NotSerializableException: org.apache.commons.fileupload.DeferredFileOutputStream
	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.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.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 org.apache.catalina.session.StandardSession.writeObject(StandardSession.java:1517)
	at org.apache.catalina.session.StandardSession.writeObjectData(StandardSession.java:959)
	at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:517)
	at org.apache.catalina.session.StandardManager.unload(StandardManager.java:463)
	at org.apache.catalina.session.StandardManager.stop(StandardManager.java:667)
	at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4519)
	at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3093)
	... 7 more

[a3737500]

首先你要明确序列化的概念。
报出此异常一般是你自身的类实现了序列化，而你调用的类没有，解决办法，都实现序列化