Question

我有这种情况：

Android App-＆gt;呼叫端点 - ＆gt; getPerson（电子邮件）
端点返回1个人对象p
我在Android应用中使用此对象并更改了一些值。
Android App-＆gt;呼叫端点 - ＆gt; updatePerson（p）

我从服务器收到此错误：


    com.google.api.server.spi.SystemService invokeServiceMethod: null
    java.lang.NullPointerException
        at com.google.appengine.api.datastore.Key.getAppId(Key.java:279)
        at com.google.appengine.api.datastore.KeyTranslator.convertToPb(KeyTranslator.java:50)
        at com.google.appengine.api.datastore.EntityTranslator.convertToPb(EntityTranslator.java:48)
        at com.google.appengine.api.datastore.AsyncDatastoreServiceImpl$4.toPb(AsyncDatastoreServiceImpl.java:178)
        at com.google.appengine.api.datastore.AsyncDatastoreServiceImpl$4.toPb(AsyncDatastoreServiceImpl.java:155)
        at com.google.appengine.api.datastore.Batcher$BatchIterator.(Batcher.java:180)
        at com.google.appengine.api.datastore.Batcher$2.(Batcher.java:317)
        at com.google.appengine.api.datastore.Batcher.getBatches(Batcher.java:317)
        at com.google.appengine.api.datastore.AsyncDatastoreServiceImpl.doBatchPut(AsyncDatastoreServiceImpl.java:365)
        at com.google.appengine.api.datastore.BaseAsyncDatastoreServiceImpl.put(BaseAsyncDatastoreServiceImpl.java:293)
        at com.google.appengine.api.datastore.BaseAsyncDatastoreServiceImpl.put(BaseAsyncDatastoreServiceImpl.java:239)
        at com.google.appengine.api.datastore.DatastoreServiceImpl.put(DatastoreServiceImpl.java:61)
        at com.google.appengine.datanucleus.WrappedDatastoreService.put(WrappedDatastoreService.java:112)
        at com.google.appengine.datanucleus.EntityUtils.putEntitiesIntoDatastore(EntityUtils.java:766)
        at com.google.appengine.datanucleus.DatastorePersistenceHandler.insertObjectsInternal(DatastorePersistenceHandler.java:314)
        at com.google.appengine.datanucleus.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:218)
        at org.datanucleus.state.JDOStateManager.internalMakePersistent(JDOStateManager.java:2381)
        at org.datanucleus.state.JDOStateManager.flush(JDOStateManager.java:3778)
        at org.datanucleus.ObjectManagerImpl.flushInternalWithOrdering(ObjectManagerImpl.java:3888)
        at org.datanucleus.ObjectManagerImpl.flushInternal(ObjectManagerImpl.java:3811)
        at org.datanucleus.ObjectManagerImpl.flush(ObjectManagerImpl.java:3751)
        at org.datanucleus.ObjectManagerImpl.preCommit(ObjectManagerImpl.java:4141)
        at org.datanucleus.ObjectManagerImpl.transactionPreCommit(ObjectManagerImpl.java:428)
        at org.datanucleus.TransactionImpl.internalPreCommit(TransactionImpl.java:398)
        at org.datanucleus.TransactionImpl.commit(TransactionImpl.java:287)
        at org.datanucleus.ObjectManagerImpl.close(ObjectManagerImpl.java:1090)
        at org.datanucleus.api.jpa.JPAEntityManager.close(JPAEntityManager.java:193)

它不是从数据存储中检索的同一对象吗？

Answer 1

您可以将主键转换为

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

如果您正在使用

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;

再次检查。

GAE更新实体中的NullPointer

1 个答案: