GAE / J数据存储区持久性Jdo删除问题

Question

目前，我的父母班级看起来像这样，

public class UserVotesJDO {

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

    @Persistent
    private String mediaId;

    @Persistent(dependent="true")
    private LikesJDO likes;

    @Persistent(dependent="true")
    private HatesJDO hates;

//带有getter和setter以及其他变量}

和我的孩子班级仇恨JDO看起来像

@PersistenceCapable(detachable = "true")
public class HatesJDO {

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

@Persistent
private int count;

private List<UserJDO> hatesUsersList;
}

其中UserJDO是另一个子类，如下所示，

@PersistenceCapable(detachable="true")
public class UserJDO {

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

@Persistent
private String userId;

@Persistent
private String userName;

@Persistent
private String fullName;

@Persistent
private String userEmail;
}

我的逻辑是，当我删除UserVote时，我不再需要那些依赖的子项和喜欢项及其UserJDO，因此当我尝试删除UserVotesJDO对象时，在控制台中收到警告，如下所示

Delete of com.shoewars.jdo.UserVotesJDO@8b4163 needs delete of related object at com.shoewars.jdo.ShoeWarsUserVotesJDO.hates but cannot delete it direct since FK is here

我不知道这一点外键是当前引用或使用.....

谁能帮我解决这个问题！

由于这是我的第一篇文章，无论如何，我不知道如何正确地发表文章，我将解释我正在尝试做的事情

我有一个存储图像ID的JDO，以及喜欢该图像和讨厌该图像的人的人信息

为此，我创建了两个JDO likesJDO和HatesJDO，分别存储列表。

因此，当我在jdo中保存有关投票的信息时，会发生以下情况

1. 获取用户信息并将其相应地存储在讨厌或喜欢的UsersList中

2. 将它们与图像ID一起添加到UserVote JDO

3. 终于坚持下去

现在，我的问题是，当我删除UserVote JDO时，我希望hatesJDO中的那些记录和likesJDO被删除，这就是为什么我添加了

@Persistent(dependent="true")
private LikesJDO likes;

@Persistent(dependent="true")
private HatesJDO hates;

这些线

但是现在，这样做时出现异常

stacktrace将像：

com.uservote.service.UserVotesOperations updateUserVoteForMedia: Cannot read fields from a deleted object
javax.jdo.JDOUserException: Cannot read fields from a deleted object
FailedObject:com.google.appengine.api.datastore.Key:UserVotesJDO(80003)/LikesJDO(1)/UserJDO(2001)
    at org.datanucleus.api.jdo.state.PersistentDeleted.transitionReadField(PersistentDeleted.java:116)
    at org.datanucleus.state.AbstractStateManager.transitionReadField(AbstractStateManager.java:838)
    at org.datanucleus.state.JDOStateManager.isLoaded(JDOStateManager.java:1699)
    at com.uservotes.jdo.UserJDO.jdoGetuserId(UserJDO.java)
    at com.uservotes.jdo.UserJDO.getUserDTO(UserJDO.java:157)
    at com.uservotes.service.InstagramApiService.convertToUserDtoList(InstagramApiService.java:555)
    at com.uservotes.jdo.LikesJDO.getLikesDTO(LikesJDO.java:95)
    at com.uservotes.jdo.uservotesUserVotesJDO.getuservotesUserVotesDTO(uservotesUserVotesJDO.java:109)
    at com.uservotes.service.UserVotesOperations.updateUserVoteForMedia(UserVotesOperations.java:242)
    at com.uservotes.service.UserVotesOperations.updateUserVoteForMediaList(UserVotesOperations.java:162)
    at com.uservotes.controller.UserVotesController.hanldeUpdateUserVotesRequest(UserVotesController.java:111)
    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 com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_$1.run(Method_.java:165)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_.privilegedInvoke(Method_.java:163)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_.invoke_(Method_.java:124)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_.invoke(Method_.java:43)
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:102)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:266)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$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:146)
    at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:447)
    at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:454)
    at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:461)
    at com.google.tracing.TraceContext.runInContext(TraceContext.java:703)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:338)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:330)
    at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:458)
    at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
    at java.lang.Thread.run(Thread.java:679)

Answer 1

似乎与延迟加载有关。 尝试在删除之前访问喜欢和讨厌（通过getLikes（）和getHates（））。