这是一年前在 GAE 上的一个老项目。它在那个时候工作得很好。最近我再次尝试在这个项目上工作，但现在效果不佳。我知道问题出在哪里，但我不知道如何解决。
添加新用户就OK了。但是当我尝试添加用户图像时，图像文件本身成功存储在 blobstore 中，但记录实体Image无法持久。
似乎 gae 无法image在 User 表中设置字段的值，并出现了一个奇怪的错误，即 String too long。它可能与 LAZY 加载内容有关。
如果你能帮助我，我会很高兴的。
这是我的实体和发生错误的代码。用户实体中的 OnetoMany 关系：
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;
@GeneratedValue(strategy = GenerationType.SEQUENCE)
Integer userid;
String username;
String password;
String email;
@OneToMany()
Collection<Image> images;
// getter and setter....
}
图像实体：
@Entity
public class Image {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;
@GeneratedValue(strategy = GenerationType.SEQUENCE)
Integer imageid;
private String name;
// full path of blobstore
private String path;
private Date uploadtime;
}
发生错误的地方：
//ImageService.java/uploadImage
user = userDao.findUser(userid);
Collection<Image> images = user.getImages();
images.add(image); // Exception occurs here
user.setImages(images);
userDao.update(user);
堆栈跟踪：
com.sun.jersey.spi.container.ContainerResponse mapMappableContainerException: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
java.lang.IllegalArgumentException: path: String properties must be 500 characters or less. Instead, use com.google.appengine.api.datastore.Text, which can store strings of any length.
at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedSingleValue(DataTypeUtils.java:242)
at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedValue(DataTypeUtils.java:207)
at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedValue(DataTypeUtils.java:173)
at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedValue(DataTypeUtils.java:148)
at com.google.appengine.api.datastore.PropertyContainer.setProperty(PropertyContainer.java:101)
at com.google.appengine.datanucleus.EntityUtils.setEntityProperty(EntityUtils.java:169)
at com.google.appengine.datanucleus.StoreFieldManager.storeFieldInEntity(StoreFieldManager.java:245)
at com.google.appengine.datanucleus.StoreFieldManager.storeStringField(StoreFieldManager.java:168)
at org.datanucleus.state.AbstractStateManager.providedStringField(AbstractStateManager.java:1438)
at com.nhm.persistence.entity.Image.jdoProvideField(Image.java)
at com.nhm.persistence.entity.Image.jdoProvideFields(Image.java)
at org.datanucleus.state.AbstractStateManager.provideFields(AbstractStateManager.java:1520)
at com.google.appengine.datanucleus.DatastorePersistenceHandler.insertObjectsInternal(DatastorePersistenceHandler.java:232)
at com.google.appengine.datanucleus.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:214)
at org.datanucleus.state.JDOStateManager.internalMakePersistent(JDOStateManager.java:2371)
at org.datanucleus.state.JDOStateManager.makePersistent(JDOStateManager.java:2347)
at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1798)
at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1892)
at org.datanucleus.store.types.sco.SCOUtils.validateObjectForWriting(SCOUtils.java:1501)
at com.google.appengine.datanucleus.scostore.AbstractFKStore.validateElementForWriting(AbstractFKStore.java:383)
at com.google.appengine.datanucleus.scostore.FKListStore.validateElementForWriting(FKListStore.java:1029)
at com.google.appengine.datanucleus.scostore.FKListStore.internalAdd(FKListStore.java:193)
at com.google.appengine.datanucleus.scostore.FKListStore.addAll(FKListStore.java:114)
at org.datanucleus.store.types.sco.backed.ArrayList.addAll(ArrayList.java:727)
at org.datanucleus.store.types.sco.backed.ArrayList.initialise(ArrayList.java:161)
at org.datanucleus.store.types.sco.SCOUtils.createSCOWrapper(SCOUtils.java:249)
at org.datanucleus.store.types.sco.SCOUtils.newSCOInstance(SCOUtils.java:140)
at org.datanucleus.state.JDOStateManager.wrapSCOField(JDOStateManager.java:2225)
at org.datanucleus.state.AbstractStateManager.setObjectField(AbstractStateManager.java:2051)
at com.nhm.persistence.entity.User.jdoSetimages(User.java)
at com.nhm.persistence.entity.User.setImages(User.java:131)
at com.nhm.web.service.ImageService.uploadImage(ImageService.java:96)
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:43)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
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$CachedChain.doFilter(ServletHandler.java:1166)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:480)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:487)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:774)
at com.google.tracing.TraceContext$DoInTraceContext.runInContext(TraceContext.java:751)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:342)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:334)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:484)
at java.lang.Thread.run(Thread.java:679)
谢谢！