这里我必须使用JPA db1，db2连接到多个数据库。我需要在我的应用程序中使用表（db2）中的数据。所以我在persistance.xml文件中为db1和db2配置了多个持久性单元。但我在启动服务器时遇到问题：
javax.persistence.PersistenceException: [PersistenceUnit: defPU] Unable to build Hibernate SessionFactory.
这是由以下原因造成的：
org.hibernate.tool.schema.spi.SchemaManagementException: Schema-validation: missing table [db2_table].
实际上它正在查找db1中的db2_table，这将不可用。这意味着它无法识别第二个持久性单元。
完整追踪：
14:05:35,409 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool -- 60) MSC000001: Failed to start service jboss.persistenceunit."default.war#defaultPU": org.jboss.msc.service.StartException in service jboss.persistenceunit."def.war#defPU": javax.persistence.PersistenceException: [PersistenceUnit: defPU] Unable to build Hibernate SessionFactory
at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1$1.run(PersistenceUnitServiceImpl.java:195)
at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1$1.run(PersistenceUnitServiceImpl.java:125)
at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:640)
at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1.run(PersistenceUnitServiceImpl.java:209)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
at org.jboss.threads.JBossThread.run(JBossThread.java:320)
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: defPU] Unable to build Hibernate SessionFactory
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:953)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:883)
at org.jboss.as.jpa.hibernate5.TwoPhaseBootstrapImpl.build(TwoPhaseBootstrapImpl.java:44)
at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1$1.run(PersistenceUnitServiceImpl.java:167)
... 7 more
Caused by: org.hibernate.tool.schema.spi.SchemaManagementException: Schema-validation: missing table [def_table]
at org.hibernate.tool.schema.internal.AbstractSchemaValidator.validateTable(AbstractSchemaValidator.java:121)
at org.hibernate.tool.schema.internal.GroupedSchemaValidatorImpl.validateTables(GroupedSchemaValidatorImpl.java:42)
at org.hibernate.tool.schema.internal.AbstractSchemaValidator.performValidation(AbstractSchemaValidator.java:89)
at org.hibernate.tool.schema.internal.AbstractSchemaValidator.doValidation(AbstractSchemaValidator.java:68)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:65)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:476)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:422)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:880)
... 9 more