我用JSF(Primefaces)和JPA创建了一个应用程序,我正在尝试将其部署在GAE上。首先,我尝试使用本地应用程序引擎 sdk。我在尝试将JPA与CloudSQL一起使用时遇到问题。我正在按照有关如何在此处使用 Eclipse 进行操作的说明:
https://developers.google.com/eclipse/docs/cloudsql-jpatools
但是我收到以下错误:
Caused by: javax.persistence.PersistenceException: Provider error. Provider: org.datanucleus.store.appengine.jpa.DatastorePersistenceProvider
at javax.persistence.Persistence.createFactory(Persistence.java:176)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:112)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:66)
at org.Handlers.EMFService.<clinit>(EMFService.java:8)
... 51 more
Caused by: java.lang.NullPointerException
at org.datanucleus.jpa.EntityManagerFactoryImpl.initialisePMF(EntityManagerFactoryImpl.java:452)
at org.datanucleus.jpa.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:355)
at org.datanucleus.store.appengine.jpa.DatastoreEntityManagerFactory.<init>(DatastoreEntityManagerFactory.java:63)
at org.datanucleus.store.appengine.jpa.DatastorePersistenceProvider.createEntityManagerFactory(DatastorePersistenceProvider.java:35)
at javax.persistence.Persistence.createFactory(Persistence.java:172)
... 54 more
更重要的是,我认为数据核心用于访问应用程序引擎数据存储。但是,我正在尝试连接到关系云sql数据库(它已启动并运行)。所以我不明白数据核与此有什么关系。
我正在使用Eclipselink来实现GAE以下指南提出的JPA规范:https://developers.google.com/eclipse/docs/cloudsql-jpatools
下面您还可以看到持久性.xml:
<persistence version="2.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="googleeclipselink"
transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>org.entities.Department</class>
<class>org.entities.Employee</class>
<class>org.entities.Partner</class>
<class>org.entities.Project</class>
<class>org.entities.User</class>
<properties>
<!-- <property name="datanucleus.NontransactionalRead" value="true" />
<property name="datanucleus.NontransactionalWrite" value="true" /> <property
name="datanucleus.ConnectionURL" value="appengine" /> -->
<property name="javax.persistence.jdbc.driver"
value="com.google.appengine.api.rdbms.AppEngineDriver" />
<property name="javax.persistence.jdbc.url"
value="jdbc:google:rdbms://fotisgonidisseerc:googlecloudsql/researchprojects" />
<property name="javax.persistence.jdbc.user" value="" />
<property name="javax.persistence.jdbc.password" value="" />
</properties>
</persistence-unit>
</persistence>
任何人都可以给我一个如何解决的提示吗?
在这个问题上花了一些时间后,我发现我必须从 WEB-INF/lib 中删除 DataNucleus 库。我还需要在类路径中添加 EclipseLink 库。这是因为我使用 EclipseLink 作为 JPA 实现。因此,DataNucleus引起了冲突,因此需要删除。我猜 Google Plug-in for Eclipse 会自动执行此操作,但显然有时它会失败。