JPA实体 - 指定持久性单位？

问题描述

我有一个使用多个持久化单元的JavaEE项目。有什么方法来指定一个特定的JPA实体属于哪个持久化单元？一些实体位于一个数据源中，而其他实体位于我的第二个数据源中。是否有办法使用注释来区分这两个注释？

I have a JavaEE project that makes use of multiple persistence units. Is there any way to specify which persistence unit a particular JPA Entity belongs to? Some entities are in one data source, while others are in my second data source. Is there a way to differentiate between the two using annotations?

推荐答案

要指定 属于，使用 persistence.xml 文件：

To specify which persistent unit an Entity belongs to, use the persistence.xml file:

<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="user" transaction-type="JTA">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <jta-data-source>jdbc/myApp</jta-data-source>
        <class>com.company.User</class>
        <exclude-unlisted-classes>true</exclude-unlisted-classes>
        <properties>
            <!-- properties -->
        </properties>
    </persistence-unit>

    <persistence-unit name="data" transaction-type="JTA">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <jta-data-source>jdbc/myApp_data</jta-data-source>
        <!--<mapping-file>META-INF/myApp_entities.xml</mapping-file> You can also use mapping files.-->
        <class>com.company.Data</class>
        <exclude-unlisted-classes>true</exclude-unlisted-classes>
        <properties>
            <!-- properties -->
        </properties>
    </persistence-unit>
</persistence>

请注意< exclude-unlisted-classes /> / code>。

Note the use of <exclude-unlisted-classes />.

这篇关于JPA实体 - 指定持久性单位？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！