在Scala中声明JPA访问的非默认JNDI连接

以下代码段适用于Scala：

class MyDAO @Inject() (jpaApi: JPAApi) {      

  @Transactional
  def someMethod = {
    jpaApi.withTransaction {   // ....

在

application.conf

中，我定义了

db.default.jndiName=DefaultDS

和

jpa.default=defaultPersistenceUnit

现在，我还需要用

jpa.other=anotherPersistenceUnit

定义另一个JNDI连接

db.other.jndName=AnotherDS

其中，

persistence.xml

是：

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
             version="2.1">

    <persistence-unit name="defaultPersistenceUnit" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <non-jta-data-source>DefaultDS</non-jta-data-source>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.HANAColumnStoreDialect"/>
        </properties>
    </persistence-unit>

    <persistence-unit name="anotherPersistenceUnit" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <non-jta-data-source>AnotherDS</non-jta-data-source>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.HANAColumnStoreDialect"/>
        </properties>
    </persistence-unit>

</persistence>

org.hibernate.jpa.HibernatePersistenceProvider
默认值
org.hibernate.jpa.HibernatePersistenceProvider
其他人

---

如何在应用程序中注入另一个JPA配置，以便与JPAApi一起使用？

您可以在

application.conf

中指定多个JPA配置：

db.default.jndiName=DefaultDS
... // other configuration for db.default
jpa.default=defaultPersistenceUnit

db.another.jndiName=AnotherDS
... // other configuration for db.another
jpa.another=anotherPersistenceUnit

在DAO中，按照当前的操作注入

JPAApi

。用于获取特定持久性单元名称的

EntityManager

：

class MyDAO @Inject() (jpaApi: JPAApi) {

  def someMethodWithDefault = {
    val em = jpaApi.em("default") // em is an EntityManager
    jpaApi.withTransaction {
      ...
    }
  }

  def someMethodWithAnother = {
    val em = jpaApi.em("another") // em is an EntityManager
    jpaApi.withTransaction {
      ...
    }
  }

此外，如果使用的是

JPAApi#with transaction

，则不需要

@Transactional

注释