运行时创建EntityManager时发生java错误EclipseLink4021为什么？

Question

我正在尝试在运行时创建EntityManager，以便可以从配置中设置不同的用户名和密码。xml

下面是创建EntityManager的代码

map.put(PersistenceUnitProperties.JDBC_USER,  SystemConfig.getConfig().getString("jdbcUser"));
map.put(PersistenceUnitProperties.JDBC_PASSWORD, SystemConfig.getConfig().getString("jdbcPassword"));
map.put(PersistenceUnitProperties.JDBC_URL, SystemConfig.getConfig().getString("jdbcUrl"));
map.put(PersistenceUnitProperties.JDBC_DRIVER, "net.sourceforge.jtds.jdbc.Driver");
EntityManager eMgr = Persistence.createEntityManagerFactory("myPU", map).createEntityManager();

我在unix中的程序结构： ~/test/myProgram。罐子 ~/test/lib/*。jar（这里所有的库和jdbc.jar）

当我在文件夹/测试中运行程序时，程序运行正常/ 然而，当我在根目录下运行程序时，我得到了异常[EclipseLink-4021]。 知道为什么吗

注意：最终我需要使用cron job来安排程序

[EL Info]: 2013-05-06 12:10:18.989--ServerSession(1729331687)--EclipseLink, version: Eclipse Persistence Services - 2.4.1.v20121003-ad44345
[EL Severe]: ejb: 2013-05-06 12:10:19.002--ServerSession(1729331687)--Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [net.sourceforge.jtds.jdbc.Driver], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
Exception in thread "main" javax.persistence.PersistenceException: Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [net.sourceforge.jtds.jdbc.Driver], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
        at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:602)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:186)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:278)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:304)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:282)
        at dcsmailcheck.MailResend.<init>(MailResend.java:61)
        at dcsmailcheck.Main.main(Main.java:49)
Caused by: Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [net.sourceforge.jtds.jdbc.Driver], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
        at org.eclipse.persistence.exceptions.DatabaseException.unableToAcquireConnectionFromDriverException(DatabaseException.java:376)
        at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:91)
        at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
        at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:685)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:215)
        at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:542)
        ... 6 more

Answer 1

由于代码在~/test文件夹中工作，因此SystemConfig.getConfig()似乎无法从该位置加载属性。确保已将属性的路径添加到类路径