如何在Spring应用程序上下文中从jpa获取jdbc数据源？

Question

如您所知，在spring applicationContext中，我们可以从persistence.xml定义EntityManagerFactory bean，如下所示：

    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="MyUnit" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="showSql" value="true" />
            <property name="generateDdl" value="false" />   
            <property name="database" value="MYSQL" />
        </bean>
    </property>
</bean>

现在，如果我要初始化数据库，如下所示：

<jdbc:initialize-database data-source="myDataSource" enabled="true">
   <jdbc:script location="classpath*:com/myapp/data*.sql"/>
</jdbc:initialize-database>

我是否必须为此配置另一个数据源bean？ 或者我可以参考上面定义的emf，或者可以参考persistence.xml？

Answer 1

 <!-- use jndi lookup, or define it by your selfe -->
 <jee:jndi-lookup id="dataSource" jndi-name="java:comp/env/jdbc/myDataSource" />  

<bean
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    id="entityManagerFactory">
    <property name="persistenceUnitName" value="persistenceUnit" />
    <property name="dataSource" ref="dataSource" />

    <!-- this is important to connect JPA and JdbcTemplate transaction control -->
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="showSql" value="false" />
        </bean>
    </property>
</bean>

<!-- jdbc templates that are equals for all databases -->
<bean class="org.springframework.jdbc.core.JdbcTemplate" id="jdbcTemplate">
    <constructor-arg ref="dataSource" />
</bean>
<bean class="org.springframework.jdbc.core.simple.SimpleJdbcTemplate" id="simpleJdbcTemplate">
    <constructor-arg ref="dataSource" />
</bean>