如何使用Spring和JPA设置多个数据源

在我们的应用程序中，我们希望使用Spring和JPA设置多个数据源。因此，我们创建了2个实体管理器，2个数据源和2个事务管理器。

网.xml

 <param-value>
    /WEB-INF/a_spring.xml
    /WEB-INF/b_spring.xml
 </param-value>

持久性.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" 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_1_0.xsd">
    <persistence-unit name="db1" transaction-type="RESOURCE_LOCAL">
        <class>com.rh.domain.RcA</class>
    </persistence-unit>

      <persistence-unit name="db2" transaction-type="RESOURCE_LOCAL">
      <class>com.rh.domain.Rcb</class>
    </persistence-unit>
</persistence>

a_spring.xml

    <?xml version="1.0" encoding="UTF-8"?>

    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:tx="http://www.springframework.org/schema/tx" 
           xmlns:aop="http://www.springframework.org/schema/aop"
           xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/tx
           http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

      <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>  
      <bean id = "RcMaintenanceService" class="com.rh.services.RcAbcMaintenanceServiceImpl" autowire="byName" />

    <aop:config>
            <aop:pointcut id="rOperation" expression="execution(* com.rh.services.*.*(..))"/>
            <aop:advisor advice-ref="txAdvice" pointcut-ref="rOperation"/>
        </aop:config>

    <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                   <tx:method name="*"/>
            </tx:attributes>
        </tx:advice>

    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
            <property name="jndiName" value="java:comp/env/jdbc/db1" />
        </bean> 
        <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
            <property name="entityManagerFactory" ref="entityManagerFactory"/>
            <property name="dataSource" ref="dataSource"/>
        </bean>

        <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
               <property name="persistenceUnitName" value="db1" />     
            <property name="dataSource" ref="dataSource"/>
            <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" />
                    <property name="databasePlatform" value="org.hibernate.dialect.MySQL5Dialect"/>
                </bean>
            </property>
            <property name="jpaDialect">
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect">
                </bean>
            </property>
        </bean>

我还向b_spring.xml声明另一个实体ManagetFactory，Transaction Manager和dataSource。

错误

豆的初始化失败;嵌套异常是 org.springframework.beans.factory.NoSuchBeanDefinitionException： 没有类型 [javax.persistence.EntityManagerFactory] 的唯一 bean 定义：预期的单 bean 但发现 2 原因：org.springframework.beans.factory.NoSuchBeanDefinitionException： 没有类型的唯一 Bean [javax.persistence.EntityManagerFactory] 定义：预期的单豆，但在 org.springframework.beans.factory.BeanFactoryUtils.beanOfTypeIncludingAncestors（BeanFactoryUtils.java：303） at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findDefaultEntityManagerFactory（PersistenceAnnotationBeanPostProcessor.java：451） at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findEntityManagerFactory（PersistenceAnnotationBeanPostProcessor.java：428） at org.springframework.orm.jpa.support.PersistenceAnPostProcessor$AnnotatedMember.resolveEntityManager（PersistenceAnnotationBeanPostProcessor.java：582） at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$AnnotatedMember.resolve（PersistenceAnnotationBeanPostProcessor.java：553） at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$AnnotatedMember.inject（PersistenceAnnotationBeanPostProcessor.java：489）