java JavaEE InvalidClassException

Question

我正在编写一个JavaEE应用程序，我有以下问题：如果我在其中一个类（TraceMessage）中初始化任何新变量并启动该应用程序，我会得到以下错误：

java.io.InvalidClassException: com.nsn.extmon.util.TraceMessage; local class incompatible: stream classdesc serialVersionUID = -5424907704652912574, local class serialVersionUID = -5748024201087063218
at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:612)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1630)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1521)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1779)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1353)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:373)
at java.util.ArrayList.readObject(ArrayList.java:771)
at sun.reflect.GeneratedMethodAccessor355.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1907)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1806)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1353)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:373)
at com.nsn.extmon.databaseHandling.ResultDataHandler.getTraceMessages(ResultDataHandler.java:137)
at com.nsn.extmon.util.TraceResultBean.traceRead(TraceResultBean.java:50)
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:606)
at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
at org.apache.myfaces.view.facelets.el.ContextAwareTagMethodExpression.invoke(ContextAwareTagMethodExpression.java:96)
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:72)
at javax.faces.component.UICommand.broadcast(UICommand.java:120)
at org.richfaces.component.RowKeyContextEventWrapper.broadcast(RowKeyContextEventWrapper.java:104)
at org.richfaces.component.UIDataAdaptor.broadcast(UIDataAdaptor.java:452)
at javax.faces.component.UIViewRoot._broadcastAll(UIViewRoot.java:1013)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:284)
at javax.faces.component.UIViewRoot._process(UIViewRoot.java:1302)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:745)
at org.apache.myfaces.lifecycle.InvokeApplicationExecutor.execute(InvokeApplicationExecutor.java:38)
at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:170)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:197)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.nsn.extmon.authentication.LoginFilter.doFilter(LoginFilter.java:33)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:611)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:409)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1044)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1721)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1679)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

我不知道这个错误是什么，我只知道如果我修改变量名，那么一切都正常。只有在声明新变量时才会出现错误

谢谢你的建议

Answer 1

在这种情况下，当您将对象反序列化（接收、加载等）到一个java进程中时，会发生InvalidClassException类异常，该进程的类版本与序列化（发送、保存等）过程中使用的类版本不同

看起来您正在将对象保存到数据库（com.nsn.extmon.databaseHandling.ResultDataHandler？）。我认为数据库中有序列化的blob，它们与类的另一个版本（“添加字段”）序列化，然后当您再次从数据库中读取它们时

如果要添加字段，则应保持serialVersionUID不变（对于非违约变更）

比如

public class TraceMessage implements Serializable {

  private static final long serialVersionUID = 1L;
  …
}

如果这是一个违反合同的变更，那么你必须确保两端的类版本相同

如果您在应用程序之间发送消息，那么您可能还想查看一个不那么脆弱的协议，比如google protobuf

编辑（参见注释）：如果您想用新类加载存储在数据库中的旧类，那么将serialVersionUID设置为-5424907704652912574