再会。我在这个应用程序中结合使用了 restlet 2.1.1 和 objectify-appengine。自从升级到 objectify 端（3.1 到 4.0b）以来，我一直在持久化任何包含非空 GeoPt 对象的实体，它以前工作过。使用的版本：* appengine-java-1.7.4 * Restlet-2.1.1 * Objectify-appengine-4.0b
启动托管模式后出现的错误似乎是一个提示：
Invoking generator org.restlet.rebind.ClientProxyGenerator
...
private com.google.appengine.api.datastore.GeoPt geoPt
com.google.appengine.api.datastore.GeoPt
Verifying instantiability
Analyzing the fields of type 'com.google.appengine.api.datastore.GeoPt' that qualify for serialization
Field 'private final float latitude' will not be serialized because it is final
Field 'private final float longitude' will not be serialized because it is final
只要它们的 GeoPt 变量为 null，我就可以保留任何实体，只要我在数据对象中保留非 null GeoPt，我就会在 appengine 控制台上报告以下错误：
12 Feb 2013 7:51:35 AM org.restlet.service.ConverterService toObject
WARNING: Unable to convert a [application/x-java-serialized-object+gwt,UTF-8] representation into an object of class
java.io.IOException: Couldn't read the GWT object representation: Invalid type signature for com.google.appengine.api.datastore.GeoPt
at org.restlet.ext.gwt.ObjectRepresentation.getObject(ObjectRepresentation.java:126)
at org.restlet.ext.gwt.GwtConverter.toObject(GwtConverter.java:149)
at org.restlet.service.ConverterService.toObject(ConverterService.java:167)
at org.restlet.resource.Resource.toObject(Resource.java:784)
at org.restlet.resource.ServerResource.doHandle(ServerResource.java:481)
at org.restlet.resource.ServerResource.doHandle(ServerResource.java:545)
at org.restlet.resource.ServerResource.put(ServerResource.java:1234)
at org.restlet.resource.ServerResource.doHandle(ServerResource.java:425)
at org.restlet.resource.ServerResource.doNegotiatedHandle(ServerResource.java:646)
at org.restlet.resource.ServerResource.doConditionalHandle(ServerResource.java:341)
at org.restlet.resource.ServerResource.handle(ServerResource.java:942)
at org.restlet.resource.Finder.handle(Finder.java:246)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.routing.Router.doHandle(Router.java:431)
at org.restlet.routing.Router.handle(Router.java:648)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.engine.application.StatusFilter.doHandle(StatusFilter.java:154)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.engine.CompositeHelper.handle(CompositeHelper.java:211)
at org.restlet.engine.application.ApplicationHelper.handle(ApplicationHelper.java:84)
at org.restlet.Application.handle(Application.java:377)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.routing.Router.doHandle(Router.java:431)
at org.restlet.routing.Router.handle(Router.java:648)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.routing.Router.doHandle(Router.java:431)
at org.restlet.routing.Router.handle(Router.java:648)
at org.restlet.routing.Filter.doHandle(Filter.java:159)
at org.restlet.routing.Filter.handle(Filter.java:206)
at org.restlet.engine.CompositeHelper.handle(CompositeHelper.java:211)
at org.restlet.Component.handle(Component.java:392)
at org.restlet.Server.handle(Server.java:516)
at org.restlet.engine.ServerHelper.handle(ServerHelper.java:72)
at org.restlet.engine.adapter.HttpServerHelper.handle(HttpServerHelper.java:152)
at org.restlet.ext.servlet.ServerServlet.service(ServerServlet.java:1089)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.googlecode.objectify.cache.AsyncCacheFilter.doFilter(AsyncCacheFilter.java:59)
at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:49)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:61)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:94)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:383)
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$RequestHandler.content(HttpConnection.java:938)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: com.google.gwt.user.client.rpc.SerializationException: Invalid type signature for com.google.appengine.api.datastore.GeoPt
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.validateTypeVersions(ServerSerializationStreamReader.java:1116)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:610)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.readObject(ServerSerializationStreamReader.java:567)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader$ValueReader$8.readValue(ServerSerializationStreamReader.java:140)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeValue(ServerSerializationStreamReader.java:425)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeClass(ServerSerializationStreamReader.java:807)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeImpl(ServerSerializationStreamReader.java:878)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:662)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:587)
at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader$ValueReader$8.readValue(ServerSerializationStreamReader.java:134)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeValue(ServerSerializationStreamReader.java:414)
at org.restlet.ext.gwt.ObjectRepresentation.getObject(ObjectRepresentation.java:122)
... 80 more
注意：在有人建议我使用 DTO 或其他框架而不是 Restlet 或 Objectify 之前，我特意选择了这种组合来实现 Restful 服务，它可以在客户端重用数据对象，而无需繁琐的 DTO 和转换。
谢谢皮埃尔