java – Spring JPA多个持久化单元：注入EntityManager

@Configuration
@EnableJpaRepositories(value = "com.company.read",entityManagerFactoryRef = "readingEntityManagerFactory",transactionManagerRef = "readingTransactionManager")
@EnableTransactionManagement
public class SpringDataJpaReadingConfiguration {

    @Bean(name = "readingEntityManagerFactory")
    public EntityManagerFactory readingEntityManagerFactory() {
        return Persistence.createEntityManagerFactory("persistence.reading");
    }

    @Bean(name = "readingExceptionTranslator")
    public HibernateExceptionTranslator readingHibernateExceptionTranslator() {
        return new HibernateExceptionTranslator();
    }

    @Bean(name = "readingTransactionManager")
    public JpaTransactionManager readingTransactionManager() {
        return new JpaTransactionManager();
    }

}

@Configuration
@EnableJpaRepositories(value = "com.company.write",entityManagerFactoryRef = "writingEntityManagerFactory",transactionManagerRef = "writingTransactionManager")
@EnableTransactionManagement
public class SpringDataJpaWritingConfiguration {

    @Bean(name = "writingEntityManagerFactory")
    public EntityManagerFactory writingEntityManagerFactory() {
        return Persistence.createEntityManagerFactory("persistence.writing");
    }

    @Bean(name = "writingExceptionTranslator")
    public HibernateExceptionTranslator writingHibernateExceptionTranslator() {
        return new HibernateExceptionTranslator();
    }

    @Bean(name = "writingTransactionManager")
    public JpaTransactionManager writingTransactionManager() {
        return new JpaTransactionManager();
    }

}

在我的存储库中,我有时需要使用EntityManager来决定如下使用：

@Repository
public class UserReadingRepository {

    @PersistenceContext(unitName = "persistence.reading")
    private EntityManager em;

    // some useful queries here
}

我使用persistence.xml中定义的持久化单元的名称：

<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_2_0.xsd"
             version="2.0">

    <persistence-unit name="persistence.reading" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <non-jta-data-source>ReadingDS</non-jta-data-source>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
            <property name="hibernate.show_sql" value="true" />
        </properties>
    </persistence-unit>

    <persistence-unit name="persistence.writing" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <non-jta-data-source>WritingDS</non-jta-data-source>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
            <property name="hibernate.show_sql" value="true" />
        </properties>
    </persistence-unit>

</persistence>

Spring throws org.springframework.beans.factory.NoSuchBeanDefinitionException：未定义名为“persistence.reading”的bean.奇怪的是,看起来Spring试图用持久化单元名称来实例化一个bean？我错配了什么吗？

更新：当我从@PersistenceContext注释中删除unitName =“persistence.reading”时,我会得到以下错误：
org.springframework.beans.factory.NoUniqueBeanDefinitionException：没有定义类型为[javax.persistence.EntityManagerFactory]的符合条件的bean：预期的单个匹配bean但是找到2：readingEntityManagerFactory,writingEntityManagerFactory

更新2：Rohit建议(在注释中)连接EntityManagerFactory.所以我试图做以下：

@PersistenceUnit(unitName = "persistence.reading")
private EntityManagerFactory emf;

但是Spring只报告：org.springframework.beans.factory.NoSuchBeanDefinitionException：没有定义名为“persistence.reading”的bean

FINAL FIX：
感谢Vlad的答案,我能够更新代码以使用以下内容(只要确保你也定义了你的dataSource bean)：

@Bean(name = "readingEntityManagerFactory")
public EntityManagerFactory readingEntityManagerFactory() {
    LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
    em.setPersistenceUnitName("persistence.reading");
    em.setDataSource(dataSource());
    em.setPackagesToScan("com.company");
    em.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
    em.afterPropertiesSet();
    return em.getObject();
}