【发布时间】：2010-11-03 13:09:05
【问题描述】：
当我尝试对我的 GWT/App Engine 应用程序的本地 JDO 数据存储执行查询时，我随机收到 org.datanucleus.exceptions.ClassNotPersistableException。这只发生在我在托管模式下运行应用程序时。当我将它部署到 Google App Engine 时，一切正常。
堆栈跟踪：
org.datanucleus.exceptions.ClassNotPersistableException: The class "com.wayd.server.beans.WinePost" is not persistable. This means that it either hasnt been enhanced, or that the enhanced version of the file is not in the CLASSPATH (or is hidden by an unenhanced version), or the Meta-Data/annotations for the class are not found.
at org.datanucleus.jdo.NucleusJDOHelper.getJDOExceptionForNucleusException(NucleusJDOHelper.java:305)
at org.datanucleus.ObjectManagerImpl.getExtent(ObjectManagerImpl.java:3700)
at org.datanucleus.jdo.JDOPersistenceManager.getExtent(JDOPersistenceManager.java:1515)
at com.wayd.server.WinePostServiceImpl.getPosts(WinePostServiceImpl.java:212)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:527)
... 25 more
Caused by: org.datanucleus.exceptions.ClassNotPersistableException: The class "com.wayd.server.beans.WinePost" is not persistable. This means that it either hasnt been enhanced, or that the enhanced version of the file is not in the CLASSPATH (or is hidden by an unenhanced version), or the Meta-Data/annotations for the class are not found.
at org.datanucleus.ObjectManagerImpl.assertClassPersistable(ObjectManagerImpl.java:3830)
at org.datanucleus.ObjectManagerImpl.getExtent(ObjectManagerImpl.java:3693)
... 32 more)
WinePost 类是一个非常简单的 JDO 持久化类：
@PersistenceCapable(identityType = IdentityType.APPLICATION) 公共类 WinePost {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Long id;
@Persistent
private User author;
@Persistent
private String grape;
@Persistent
private String comment;
public WinePost(final User author, final String grape,
final String comment) {
super();
this.grape = grape;
this.comment = comment;
}
public User getAuthor() {
return author;
}
public void setAuthor(final User author) {
this.author = author;
}
public Long getId() {
return id;
}
public void setId(final Long id) {
this.id = id;
}
public String getGrape() {
return grape;
}
public void setGrape(final String grape) {
this.grape = grape;
}
public String getComment() {
return comment;
}
public void setComment(final String comment) {
this.comment = comment;
}
public String getUserNickname() {
String retVal = null;
if (author != null) {
retVal = author.getNickname();
}
return retVal;
}
public WinePostModel getWinePostModel() {
final WinePostModel winePostModel = new WinePostModel(grape, vintage, getUserNickName());
return winePostModel;
}
}
数据存储区查询通过以下方法进行：
public ArrayList<WinePostModel> getPosts() {
final ArrayList<WinePostModel> posts = new ArrayList<WinePostModel>();
final PersistenceManager persistenceManager = PMF.get()
.getPersistenceManager();
final Extent<WinePost> winePostExtent = persistenceManager.getExtent(
WinePost.class, false);
for (final WinePost winePost : winePostExtent) {
posts.add(winePost.getWinePostModel());
}
winePostExtent.closeAll();
return posts;
}
【问题讨论】：
标签： java google-app-engine gwt