我在哪里可以使用JPA / Google App Engine设置TransactionOptions？ [英] Where do I set TransactionOptions with JPA / Google App Engine?

问题描述

  javax.persistence.PersistenceException：非法参数
 at org .datanucleus.api.jpa.NucleusJPAHelper.getJPAExceptionForNucleusException（NucleusJPAHelper.java:298）
在org.datanucleus.api.jpa.JPAEntityTransaction.commit（JPAEntityTransaction.java:122）
引起的：java.lang中.IllegalArgumentException：跨集团的交易需要被明确指定，见TransactionOptions.Builder.withXGfound都
元素{
型： 事件 
编号：0x11000000000000 
} 
和元素{
类型：用户
 id：0x14000000000000 
} 
  

与用户之间存在双向的多对多关系。当我插入一个新事件并将其绑定到事务中的现有用户时，我得到了上述异常。
从错误消息中我看到我需要调整 TransactionOptions 。我可以在哪里设置这些选项？

解决方案

在 persistence.xml $ b

 < property name =datanucleus.appengine.datastoreEnableXGTransactionsvalue =true/> 
  

目前没有办法为单个JDO或JPA事务启用XG事务。相反，您可以为所有交易指定此值。 [docs]

I use JPA within GAE to persist objects.

javax.persistence.PersistenceException: Illegal argument
    at org.datanucleus.api.jpa.NucleusJPAHelper.getJPAExceptionForNucleusException(NucleusJPAHelper.java:298)
    at org.datanucleus.api.jpa.JPAEntityTransaction.commit(JPAEntityTransaction.java:122)
Caused by: java.lang.IllegalArgumentException: cross-group transaction need to be explicitly specified, see TransactionOptions.Builder.withXGfound both 
Element {
  type: "Event"
  id: 0x11000000000000
}
and Element {
  type: "User"
  id: 0x14000000000000
}

There is a bidirectional Many-To-Many relationship between Event and User. When I insert a new Event and bound it to existing Users inside a transaction, I get the above exception. From the error message I see that I need to tweak TransactionOptions. Where can I set these options?

解决方案

Set the following property in persistence.xml:

<property name="datanucleus.appengine.datastoreEnableXGTransactions" value="true" />

There is currently no way to enable XG transactions for an individual JDO or JPA transaction. Instead, you specify this for all transactions. [docs]

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