GAE会议。java.io.NotSerializableException:sun.nio.cs.UTF_8问题

我对谷歌应用程序引擎还很陌生，在我第一次部署新应用程序时遇到了一个问题。 我正在尝试在会话中存储一些对象。在我的本地主机上一切正常。 下面的堆栈跟踪指向不可序列化的类“Group”——但它是可序列化的。希望有人能帮忙。提前谢谢

/CreateGroup.action
java.lang.RuntimeException: java.io.NotSerializableException: sun.nio.cs.UTF_8
    at com.google.apphosting.runtime.jetty.SessionManager.serialize(SessionManager.java:358)
    at com.google.apphosting.runtime.jetty.DatastoreSessionStore.createEntityForSession(DatastoreSessionStore.java:71)
    at com.google.apphosting.runtime.jetty.DatastoreSessionStore.saveSession(DatastoreSessionStore.java:93)
    at com.google.apphosting.runtime.jetty.SessionManager$AppEngineSession.save(SessionManager.java:153)
    at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:41)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:249)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:135)
    at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:391)
    at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:160)
    at java.lang.Thread.run(Thread.java:679)
Caused by: java.io.NotSerializableException: sun.nio.cs.UTF_8
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1180)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1528)
    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:438)
    at com.xxxxxxxxx.xxxxxxxxx.model.Group.writeObject(Group.java)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:962)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1480)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1416)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1174)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:346)
    at java.util.HashMap.writeObject(HashMap.java:1018)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:962)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1480)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1416)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1174)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:346)
    at com.google.apphosting.runtime.jetty.SessionManager.serialize(SessionManager.java:355)
    ... 23 more

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java具有以下字段（CommonPool类型也实现了可序列化）：

看起来您已经“覆盖”了magic writeObject方法来自定义组的序列化方式，其中有一个sun.nio.cs.UTF_8的实例。您说CommonPool是可序列化的，但仅仅实现接口并不能使它成为可序列化的。它必须是可序列化的，否则会失败。那里还有一把“钥匙”。这也可能是你问题的根源。

好吧，所以我想出来了（我确实感到有点尴尬） 我在Group.java中忽略了一个字段（不在上面的代码存根中），它是不可序列化的。。。愚蠢的我。

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很抱歉给您带来不便，感谢您的快速回复。

感谢您的快速回复。重写writeObject对我来说似乎是个谜；-）我很确定我没有这么做。CommonPool的字段只是double和String类型，正如您在类组中指出的那样。类型键只是appengine数据存储的标准com.google.appengine.api.datastore.Key，我相信它是可序列化的。

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Group implements Serializable {

    private static final long serialVersionUID = -5274228818084728571L;

    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Key key;

    @Persistent
    private String name;

    @Persistent
    private int memberCount;

    @Persistent
    private int maxMemberCount;

    @Persistent
    private String currencySymbol;

    @Persistent
    private String url;

    @Persistent
    private Date createdOn;

    @Persistent
    private CommonPool pool;