java - DataNucleus/NeoDatis - 数据库连接似乎关闭，导致持久对象丢失

Question

使用 DataNucleus 我在下面的第二个 INFO 语句(从底部开始的第二个条目)中发现了一个问题。

在使用 makePersistent() 持久化对象后尝试读取或编辑该对象时，我只得到空值，INFO 日志表明该对象不再由持久化管理器管理(尽管我在 makePersistent() 调用后立即执行这些编辑)。

我的猜测是，与我的数据存储(本地嵌入/文件模式下的 NeoDatis)的连接正在关闭，因此持久性管理器停止管理它。但我只是使用 DataNucleus org.datanucleus.jdo.JDOPersistenceManagerFactory 类来创建连接。

知道为什么会发生这种情况吗？我是否认为关闭连接消息是问题所在，是否正确？

为了简洁起见，缩短了 FQDN，并删除了无关的日志:

DEBUG DataNucleus.Persistence  - Making object persistent : "a.b.c.User@22a866a9"
INFO  DataNucleus.Persistence  - Managing Persistence of Class : a.b.c.User [Table : (none), InheritanceStrategy : new-table]
DEBUG DataNucleus.Connection  - Connection added to the pool : [o.dn.s.neodatis.ConnectionFactoryImpl$ManagedConnectionImpl@28f337b, null] for key=o.dn.ExecutionContextImpl@59c12050 in factory=ConnectionFactory:tx[o.dn.s.neodatis.ConnectionFactoryImpl@3b626c6d]
DEBUG DataNucleus.Datastore  - Opening NeoDatis ODB for "neodatis:file:database/neodatis_primary_datastore.odb" : org.neodatis.odb.impl.main.LocalODB@13a183d2
DEBUG DataNucleus.Datastore.Persist  - Object "a.b.c.User@22a866a9" being inserted into NeoDatis with all reachable objects
DEBUG DataNucleus.Datastore.Persist  - Object "a.b.c.User@22a866a9" (id="15) persisted to NeoDatis
DEBUG DataNucleus.Datastore  - Committing NeoDatis ODB for "neodatis:file:database/neodatis_primary_datastore.odb" : org.neodatis.odb.impl.main.LocalODB@13a183d2
DEBUG DataNucleus.Connection  - Connection removed from the pool : [o.dn.s.neodatis.ConnectionFactoryImpl$ManagedConnectionImpl@28f337b, null] for key=o.dn.ExecutionContextImpl@59c12050 in factory=ConnectionFactory:tx[o.dn.s.neodatis.ConnectionFactoryImpl@3b626c6d]
DEBUG DataNucleus.Connection  - The connection has been closed : [o.dn.s.neodatis.ConnectionFactoryImpl$ManagedConnectionImpl@28f337b, null]
DEBUG DataNucleus.Reachability  - Performing check of objects for "persistence-by-reachability" (commit) ...
DEBUG DataNucleus.Cache  - Object "a.b.c.User@22a866a9" (id="15") added to Level 2 cache (loadedFlags="[YYYYYYY]", relationFields="null")
DEBUG DataNucleus.Transaction  - Committing [DataNucleus Transaction, ID=Xid=, enlisted resources=[]]
DEBUG DataNucleus.Lifecycle  - Object "a.b.c.User@22a866a9" (id="15") has a lifecycle change : "P_NEW"->"HOLLOW"
DEBUG DataNucleus.Transaction  - Object "a.b.c.User@22a866a9" (id="15") being evicted from transactional cache
DEBUG DataNucleus.Transaction  - Transaction committed in 7 ms
DEBUG DataNucleus.Lifecycle  - Object "a.b.c.User@22a866a9" (id="15") has a lifecycle change : "HOLLOW"->"P_NONTRANS"
DEBUG DataNucleus.Persistence  - Fetching object "a.b.c.User@22a866a9" (id=15) fields [authorities,createdFromIP,dateCreated,password,timeZoneID,username]
DEBUG DataNucleus.Datastore.Retrieve  - Object "a.b.c.User@22a866a9" (id="15") being retrieved from NeoDatis
DEBUG DataNucleus.Connection  - Connection added to the pool : [o.dn.s.neodatis.ConnectionFactoryImpl$ManagedConnectionImpl@39673d71, null] for key=o.dn.ExecutionContextImpl@59c12050 in factory=ConnectionFactory:tx[o.dn.s.neodatis.ConnectionFactoryImpl@3b626c6d]
DEBUG DataNucleus.Datastore  - Opening NeoDatis ODB for "neodatis:file:database/neodatis_primary_datastore.odb" : org.neodatis.odb.impl.main.LocalODB@621f6c18
DEBUG DataNucleus.Datastore  - Committing NeoDatis ODB for "neodatis:file:database/neodatis_primary_datastore.odb" : org.neodatis.odb.impl.main.LocalODB@621f6c18
DEBUG DataNucleus.Connection  - Connection removed from the pool : [o.dn.s.neodatis.ConnectionFactoryImpl$ManagedConnectionImpl@39673d71, null] for key=o.dn.ExecutionContextImpl@59c12050 in factory=ConnectionFactory:tx[o.dn.s.neodatis.ConnectionFactoryImpl@3b626c6d]
DEBUG DataNucleus.Connection  - The connection has been closed : [o.dn.s.neodatis.ConnectionFactoryImpl$ManagedConnectionImpl@39673d71, null]
INFO  DataNucleus.Persistence  - Request to populate fields of a.b.c.User@22a866a9 but this object is no longer managed by NeoDatis so replacing with a.b.c.User@7cf1cdfb
DEBUG DataNucleus.Datastore.Retrieve  - Execution Time = 5 ms

Answer 1

我喜欢学习新事物，但为什么有时这是一个如此痛苦的过程？好吧，这是一个答案，不是一个问题......

所以，我确实删除了一个可以帮助其他人看到问题的关键日志行:

1795 [main] INFO DataNucleus.Transaction  - Non-tx updates are being committed to the datastore

重点是，上述问题是由于我在事务之外执行操作造成的。

实际上这只是第一步，真正发生的是我正在针对与事务启动时不同的 PersistenceManager 执行操作。

我使用 Spring 管理事务，但我调用了 jdoPersistenceManager.getPersistenceManager()，这产生了一个新的 PersistenceManager 实例(详细的调试 session 发现了这一点)。

我应该使用 spring 来获取 spring 事务定义的 PersistenceManager 。最终，这意味着在我的 DAO 对象中扩展JdoDaoSupport。

我现在感觉更聪明了，但不知何故，学习永无止境。