Question

我有两个实体：Customer和Relation 客户（X）可以与多个客户建立联系。另一位客户（Y）可以与X的相同客户（或非客户）建立联系。我还需要开始日期和关系状态。

我决定使用Unowned OneToMany关系。

// Customer entity
@PersistenceCapable(detachable = "true")
public class Customer implements Serializable {

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

    @Persistent
    private Set<Relation> relations = new HashSet<Relation>();

    // other fields, getters and setters here
}

// --------------------------------------------------------

// Relation entity
@PersistenceCapable(detachable = "true")
public class Relation implements Serializable {

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

    // Customer who wants to be connected to another customer
    @Persistent
    private Key sourceKey;

    // Customer who needs to accept the request
    @Persistent
    private Key targetKey;

    @Persistent
    private Date date;

    @Persistent
    private String status;
    // other fields, getters and setters here
}

然后我创建了两个客户......并尝试在他们之间建立关系：

PersistenceManager pm = pmf.getPersistenceManager();

// retrives the 2 customers by name 
// 
// ...

// Creating a relationship between them

relation = new Relation();
relation.setDate(new Date());
relation.setStatus("AWAITING");

// first customer key
relation.setSourceKey(customerFindByName.getKey());

// second customer
relation.setTargetKey(targetFindByName.getKey());

// add relation
customerFindByName.addRelation(relation);
targetFindByName.addRelation(relation);

pm.makePersistent(relation);

但我在此行NucleusObjectNotFoundException

pm.makePersistent(relation);

遇到此例外（

Could not retrieve entity of kind Relation with key     Customer(5066549580791808)/Relation(4785074604081152)
org.datanucleus.exceptions.NucleusObjectNotFoundException: Could not retrieve entity of kind Relation with key Customer(5066549580791808)/Relation(4785074604081152)
at com.google.appengine.datanucleus.DatastoreExceptionTranslator.wrapEntityNotFoundException(DatastoreExceptionTranslator.java:61)
at com.google.appengine.datanucleus.EntityUtils.getEntityFromDatastore(EntityUtils.java:670)
at com.google.appengine.datanucleus.DatastorePersistenceHandler.fetchObject(DatastorePersistenceHandler.java:543)
at org.datanucleus.state.JDOStateManager.loadFieldsFromDatastore(JDOStateManager.java:1638)
at org.datanucleus.state.JDOStateManager.refreshLoadedFields(JDOStateManager.java:1541)
at org.datanucleus.api.jdo.state.Hollow.transitionMakeTransactional(Hollow.java:71)
at org.datanucleus.state.JDOStateManager.attachCopy(JDOStateManager.java:3194)
at org.datanucleus.ObjectManagerImpl.attachObjectCopy(ObjectManagerImpl.java:2488)
at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1818)
at org.datanucleus.ObjectManagerImpl.persistObjectWork(ObjectManagerImpl.java:1745)
at org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:1602)
at org.datanucleus.api.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:731)
at org.datanucleus.api.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:756)
at com.clebettre.social.datastore.CustomerDatastoreImpl.relationRequestAwaiting(CustomerDatastoreImpl.java:139)
at com.clebettre.social.services.customer.CustomerServiceImpl.relationRequestAwaiting(CustomerServiceImpl.java:51)
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 com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:115)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy23.relationRequestAwaiting(Unknown Source)
at com.clebettre.social.web.relation.RelationController.relationRequestAwaiting(RelationController.java:38)

）

我不明白为什么我得到这个例外，我想对此有一些解释，以及如何解决这个错误以便正确地保持我的关系？

感谢您的帮助。

JDO / GAE：创建oneToMany关系时的NucleusObjectNotFoundException

0 个答案: