问题
we are haunted by occasional occurences of exceptions such as:
com.google.gwt.user.client.rpc.SerializationException: Type 'xxx' was not assignable to 'com.google.gwt.user.client.rpc.IsSerializable' and did not have a custom field serializer.For security purposes, this type will not be serialized.: instance = xxx at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:610) at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:129) at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:152) at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:534) at com.google.gwt.user.server.rpc.RPC.encodeResponse(RPC.java:609) at com.google.gwt.user.server.rpc.RPC.encodeResponseForSuccess(RPC.java:467) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:564) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188) at de.softconex.travicemanager.server.TraviceManagerServiceImpl.processCall(TraviceManagerServiceImpl.java:615) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224) at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) at javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262) at org.apache.coyote.ajp.AjpAprProcessor.process(AjpAprProcessor.java:419) at org.apache.coyote.ajp.AjpAprProtocol$AjpConnectionHandler.process(AjpAprProtocol.java:378) at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1508) at java.lang.Thread.run(Thread.java:619)
The application is normally running fine. The indicated class implements Serializable (the whole object graph).
So far the only patterns / observations are:
we seem to have the issue only when the application is used inside an iframe
the problem seems to happen when a new version of the application has been deployed
running firefox in privacy mode (disabling all caches etc.) doesn't fix the problem
Any ideas?
Holger
回答1:
did you check http://code.google.com/webtoolkit/doc/latest/tutorial/RPC.html#serialize
the article says:
It has a default (zero argument) constructor with any access modifier (e.g. private Foo(){} will work)
I'm allways forgetting zeroargument const. when I am making a serializable object :D
回答2:
Very possible reason - older version of client is still cached in browser. It sends rpc requests, but server is already restarted and have newer versions of rpc files (*.symbolMap)
回答3:
I encountered the problem when I used Tomcat6 + Devmode in Ubuntu Lucid amd64. Using com.google.gwt.user.client.rpc.IsSerializable instead of java.io.Serializable seemed solved the problem.
回答4:
I assume you're running the application on localhost and in hosted mode? If so, you might want to keep an eye on the work directory (or the equivalent directory if you're not running the application in a tomcat server). Check the webapp's folder for serialization policiy files (*.gwt.rpc).
It's possible they're not loaded correctly, the only workaround we have found so far, is to restart your server after each serialization fault.
The problem is due to the fact GWT will generate its serialization policy files at run time, assuming you're running in hosted mode. In compiled mode, GWT will generate all necessary files at compile time. AFAIK, tomcat's unable to load in the resource files at run time and hence will not include the serialization files each time they are needed for the first time.
When restarting the server, tomcat's able to pick up the previously generated file and hence you shouldn't receive the same error after restarting.
Can you verify this?
回答5:
If you are running on JBoss, this might be due to the fact that the previously deployed application is not deleted when undeployed. To fix this, you must modify the following file in JBoss: ${JBOSS_HOME}/server/default/deployers/jbossweb.deployer/META-INF/war-deployers-jboss-beans.xml and set the following attribute to true: deleteWorkDirOnContextDestroy
When the previously deployed application is not cleaned up, GWT can be confused about which RPC file it needs to load and you end up with those SerializationException
回答6:
I had the same problem and I found a solution from another person:
"There is a possibility that you have a class which implements Serializable and you have an attribute field within that class which is not Serializable hence you might be getting this exception."
Many thanks to that person :)
My advice is to make all fields (which are not primitive types) in your class to implement Serializable also! This solved my problem.
回答7:
This problem occurs when a GWT 2.5 application is compiled using JDK 1.7. GWT 2.5 supports JDK 1.6 and using this version of JDK will fix this issue.
回答8:
So the RPC files are unique because they are loaded by servlets as well as being used in GWT. See http://code.google.com/webtoolkit/release-notes.html#Release_Notes_1_4_59 where it says "This file must be deployed to your web server as a public resource, accessible from a RemoteServiceServlet via ServletContext.getResource()"
Is it possible the new application is being reloaded dynamically and getResource is failing in some way? Does restarting the application fix things?
回答9:
I've had the same error and fix this by clean the browse cache and navigation history.
回答10:
I was getting a SerializationException also but I was also seeing this error showing up right before the serialization exception:
[uptimereports/2.340102563369350884].: Example : error : cannot find template registration-confirmation.vm
It turned out to be a problem finding my velocity template. Once I fixed that problem the SerializationException stopped showing up, so if you follow Kerem's advice and still have problems, look for other exceptions in your log.
回答11:
The best way to know the exact issue is to compile your code using -logLevel DEBUG or TRACE and check inside Validating Units. I am sure you would be able to find out the exact issue with line numbers as well.
回答12:
tu obtiens cette erreur parce que tu essaies de faire passer une liste d'objets non sérialisée par le tunel rpc. tu devras d'abord sérialiser ta liste d'objet avant le tranfert vers le tunel rpc. pour sérialiser ta liste, tu peux faire un truc du genre ci-dessous et faire passer ce nouveau objet vers le tunel rpc
public class ListObjet<T> implements Serializable{
/** Constant used for serialization purpose (serial number). */
private static final long serialVersionUID = 8153484637403868153L;
private List<T> listObjet;
public List<T> getListOjets()
{
return listObjet;
}
public void setListObjet(List<T> m_listObjet)
{
this.listObjet= m_listObjet;
}
}
Merci
Lagrange
来源：https://stackoverflow.com/questions/2122798/gwt-occasional-com-google-gwt-user-client-rpc-serializationexception