如何从JPA persistence.xml中外部化属性？

问题描述

我想将一些hibernate配置放在一个属性文件中，以便在没有构建和部署的情况下进行编辑。

我试图通过遵循来自

的说明

app.properties：

  hibernate.show_sql = true 
 hibernate.dialect = org.hibernate.dialect.MySQLDialect 
 hibernate.hbm2ddl.auto = validate 
 hibernate.show_sql = true 
 hibernate.format_sql = true 
 hibernate.default_schema = myschema 
  

persistence.xml

 <？xml version =1.0encoding =UTF-8？> 
 < persistence 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_1_0.xsd
 version = 1.0 > 
 
< persistence-unit name =pu> 
< provider> org.hibernate.ejb.HibernatePersistence< / provider> 
< jta-data-source> jdbc / appDatasource< / jta-data-source> 
<属性> 
< property name =jboss.entity.manager.factory.jndi.namevalue =java：/ appEntityManagerFactory/> 
< / properties> 
< / persistence-unit> 
 
< /持久性> 
  

在初始化代码中，应用程序执行以下序列（找到属性），

 属性props = new Properties（）; 
 InputStream is = ClassLoader.getSystemResourceAsStream（app.properties）; 
 props.load（is）; 
 Persistence.createEntityManagerFactory（pu，props）; 
  

但失败并显示错误讯息：

 INFO [SessionFactoryImpl]构建会话工厂
 INFO [SessionFactoryObjectFactory]没有将工厂绑定到JNDI，没有配置JNDI名称
 ERROR [STDERR] javax.persistence.PersistenceException： PersistenceUnit：pu]无法构建EntityManagerFactory 
  

有没有人知道我的配置有什么问题？

版本：JBoss 4.3
Seam：2.1.2

编辑：

JBoss JNDI将pu作为持久性单元：

  persistence.units：ear = app.ear，jar = app.jar，unitName = pu（class：org.hibernate.impl.SessionFactoryImpl）
  

解决方案

作为当前方法的替代方案，并且由于您使用的是Hibernate，因此您可以使用Hibernate通过声明 hibernate.cfg.xml 文件使用 hibernate。 ejb.cfgfile 属性，如下所示：

 < persistence> 
< persistence-unit name =manager1transaction-type =JTA> 
< jta-data-source> java：/ DefaultDS< / jta-data-source> 
<属性> 
< property name =hibernate.ejb.cfgfilevalue =/ hibernate.cfg.xml/> 
< / properties> 
< / persistence-unit> 
< /余辉> 
  

我的理解是 hibernate.cfg.xml



参考文献

• Hibernate Entity Manager参考指南
  
  
  
  
  
  

I would like to put some of the hibernate configuration in a property file to make it editable without build and deploy.

I tried to solve my problem by following the instructions from Create JPA EntityManager without persistence.xml configuration file

app.properties:

hibernate.show_sql=true
hibernate.dialect=org.hibernate.dialect.MySQLDialect
hibernate.hbm2ddl.auto=validate
hibernate.show_sql=true
hibernate.format_sql=true
hibernate.default_schema=myschema

persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Persistence deployment descriptor for dev profile -->
<persistence 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_1_0.xsd"
             version="1.0">

   <persistence-unit name="pu">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>jdbc/appDatasource</jta-data-source>
      <properties>
         <property name="jboss.entity.manager.factory.jndi.name" value="java:/appEntityManagerFactory"/>
      </properties>
   </persistence-unit>

</persistence>

In the initialization code the application executes the following sequence, (which finds the properties),

Properties props = new Properties();
InputStream is = ClassLoader.getSystemResourceAsStream( "app.properties" );
props.load( is );
Persistence.createEntityManagerFactory( "pu", props );

but fails with the error message:

 INFO  [SessionFactoryImpl] building session factory
 INFO  [SessionFactoryObjectFactory] Not binding factory to JNDI, no JNDI name configured
ERROR [STDERR] javax.persistence.PersistenceException: [PersistenceUnit: pu] Unable to build EntityManagerFactory

Does anyone have an idea what could be wrong with my configuration?

Versions: JBoss 4.3Seam: 2.1.2

EDIT:

JBoss JNDI enlists "pu" as persistence unit:

persistence.units:ear=app.ear,jar=app.jar,unitName=pu (class: org.hibernate.impl.SessionFactoryImpl)

解决方案

As an alternative to your current approach and since you're using Hibernate, you could use Hibernate to configure JPA by declaring a hibernate.cfg.xml file using the hibernate.ejb.cfgfile property, like this:

<persistence>
 <persistence-unit name="manager1" transaction-type="JTA">
    <jta-data-source>java:/DefaultDS</jta-data-source>
    <properties>
       <property name="hibernate.ejb.cfgfile" value="/hibernate.cfg.xml"/>
    </properties>
 </persistence-unit>
</persistence>

My understanding is that the hibernate.cfg.xml is just supposed to be on the classpath (so it could be outside the packaged archive).

References

• Hibernate Entity Manager Reference Guide
  • Table 2.1. Hibernate Entity Manager specific properties

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