Eclipselink 持久性单元加载异常答案

【问题标题】：Eclispelink PersistenceUnitLoadingExceptionEclipselink 持久性单元加载异常
【发布时间】：2012-11-15 19:08:42
【问题描述】：

我在 Eclispelink 2.4.1 下面遇到了PersistenceUnitLoadingException，堆栈跟踪说明了什么？

Exception in thread "main" java.lang.ExceptionInInitializerError
Caused by: Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@45a877
Internal Exception: Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@45a877
Internal Exception: java.lang.NullPointerException
    at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionSearchingForPersistenceResources(PersistenceUnitLoadingException.java:127)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:118)
    at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
    at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
    at com.mypkg.Main.<clinit>(Main.java:12)
Caused by: Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@45a877
Internal Exception: java.lang.NullPointerException
    at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionSearchingForPersistenceResources(PersistenceUnitLoadingException.java:127)
    at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.findPersistenceArchives(PersistenceUnitProcessor.java:321)
    at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.findPersistenceArchives(PersistenceUnitProcessor.java:272)
    at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfoInArchives(JPAInitializer.java:150)
    at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfo(JPAInitializer.java:135)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:76)
    ... 3 more
Caused by: java.lang.NullPointerException
    at org.eclipse.persistence.internal.jpa.deployment.DirectoryArchive.init(DirectoryArchive.java:79)
    at org.eclipse.persistence.internal.jpa.deployment.DirectoryArchive.init(DirectoryArchive.java:96)
    at org.eclipse.persistence.internal.jpa.deployment.DirectoryArchive.<init>(DirectoryArchive.java:74)
    at org.eclipse.persistence.internal.jpa.deployment.DirectoryArchive.<init>(DirectoryArchive.java:54)
    at org.eclipse.persistence.internal.jpa.deployment.ArchiveFactoryImpl.createArchive(ArchiveFactoryImpl.java:89)
    at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.findPersistenceArchives(PersistenceUnitProcessor.java:297)
    ... 7 more
Could not find the main class: com.mypkg.Main.  Program will exit.

@EDIT

我在下面的 Eclipse 下有项目结构，它与 Hibernate 作为持久性提供者配合得很好。

bin
  |_META-INF
  |        |_persistence.xml
  |_com
      |_mypkg
            |_Main.class
            |_MyEntity.class

【问题讨论】：

好像找不到persistence.xml文件。
我猜persistence.xml 位置很好，可以通过Hibernate 找到。你能检查我上面的更新吗？谢谢！
File.listFiles() 调用的元素之一为空。我从未见过这个问题，但是 EclipseLink 2.5 中有一些小的代码更改 - 你可以试一试并发布堆栈跟踪以查看它是否更改？
你使用的是什么 JVM/环境？
Eclipse 3.7.2 和 JDK 1.6.0_37 在 Linux 3.2.0-33-generic-pae（32 位 Ubuntu 12.04.1）上

标签： jpa jpa-2.0 eclipselink

【解决方案1】：

升级到 eclipselink 到以下为我解决了这个问题：

<dependency>
    <groupId>org.eclipse.persistence</groupId>
    <artifactId>org.eclipse.persistence.jpa</artifactId>
    <version>2.7.3</version>
</dependency>

【讨论】：