Spring + JPA +多个持久性单元：注入EntityManager [英] Spring + JPA + multiple persistence units: Injecting EntityManager

问题描述

我需要使用一个数据库进行查询（非修改），一个用于命令（修改）。我使用的是Spring Data JPA，所以我有两个配置类：


$ @ $ 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）;

$ b $ @Bean（name =readingExceptionTranslator）
public HibernateExceptionTranslator readingHibernateExceptionTranslator（）{
return new HibernateExceptionTranslator（）;

$ b $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 ）{
返回Persistence.createEntityManagerFactory（persistence.writing）;


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

$ b $Bean（name =writingTransactionManager）
public JpaTransactionManager writingTransactionManager（）{
return new JpaTransactionManager（）;
}

}

在我的资源库中，有时需要

  @Repository 
 public class UserReadingRepository {
 
 @PersistenceContext（unitName =persistence.reading）
 private EntityManager em; 
 
 //一些有用的查询在这里
} 
  

我是使用 persistence.xml 中定义的持久单元名称：

 < 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.readingtransaction-type =RESOURCE_LOCAL> 
< provider> org.hibernate.jpa.HibernatePersistenceProvider< / provider> 
< non-jta-data-source> ReadingDS< / non-jta-data-source> 
<属性> 
< property name =hibernate.dialectvalue =org.hibernate.dialect.MySQLDialect/> 
< property name =hibernate.show_sqlvalue =true/> 
< / properties> 
< / persistence-unit> 
 
< persistence-unit name =persistence.writingtransaction-type =RESOURCE_LOCAL> 
< provider> org.hibernate.jpa.HibernatePersistenceProvider< / provider> 
< non-jta-data-source> WritingDS< / non-jta-data-source> 
<属性> 
< property name =hibernate.dialectvalue =org.hibernate.dialect.MySQLDialect/> 
< property name =hibernate.show_sqlvalue =true/> 
< / properties> 
< / persistence-unit> 
 
< /持久性> 
  

Spring抛出 org.springframework.beans.factory.NoSuchBeanDefinitionException：No bean named 'persistence.reading'被定义。奇怪的是，它看起来像Spring试图用持久单元名称实例化一个bean ？我是否错误配置了某些内容？

更新：当我删除 unitName =persistence.reading from @PersistenceContext注解，我将得到以下错误：
org.springframework.beans.factory.NoUniqueBeanDefinitionException：没有定义[javax.persistence.EntityManagerFactory]类型的合格bean被定义：expected单个匹配bean，但找到2：readingEntityManagerFactory，writingEntityManagerFactory

$ b

更新2 ：建议（在评论中）连线 EntityManagerFactory 代替。所以我试图做到以下几点：$ b​​
$ b

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

但Spring仅报告： org.springframework.beans.factory.NoSuchBeanDefinitionException：没有定义名为'persistence.reading'的bean

最终修正：
感谢Vlad的回答，我可以更新代码以使用以下代码（只要确保定义了 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（）; 
返回em.getObject（）; 
 
  

解决方案 EntityManageFactory 不是正确配置。您应该使用 LocalContainerEntityManagerFactoryBean 来代替：

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

另外 JpaTransactionManager 也是错配的。它应该是这样的：



  @Bean（name =readingTransactionManager）
 public PlatformTransactionManager readingTransactionManager（）{
 JpaTransactionManager transactionManager = new JpaTransactionManager（）; 
 transactionManager.setEntityManagerFactory（readingEntityManagerFactory（））; 
返回transactionManager; 
 
 $ / code> 

您需要为读取和写入EntityManager配置执行相同的操作。


I need to use one database for queries (non-modifying) and one for commands (modifying). I am using Spring Data JPA, so I have two configuration classes:

@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();
    }

}

In my repository I sometimes need to decide with EntityManager to use like so:

@Repository
public class UserReadingRepository {

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

    // some useful queries here
}

I am using persistence unit's name as defined in my persistence.xml:

<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: No bean named 'persistence.reading' is defined. Oddly, it looks like Spring tries to instantiate a bean with persistence unit name? Did I misconfigure something?

UPDATE: When I remove unitName = "persistence.reading" from @PersistenceContext annotation, I will get following error instead: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [javax.persistence.EntityManagerFactory] is defined: expected single matching bean but found 2: readingEntityManagerFactory,writingEntityManagerFactory

UPDATE 2: Rohit suggested (in the comment) to wire EntityManagerFactory instead. So I tried to do the following:

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

but Spring only reports: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'persistence.reading' is defined

FINAL FIX: Thanks to Vlad's answer, I was able to update the code to use the following (just make sure you define your dataSource bean as well):

@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();
}

解决方案

The EntityManageFactory is not properly configured. You should use a LocalContainerEntityManagerFactoryBean instead:

@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();
}

Also the JpaTransactionManager is miss-configured too. It should be something like:

@Bean(name = "readingTransactionManager")
public PlatformTransactionManager readingTransactionManager(){
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(readingEntityManagerFactory());
    return transactionManager;
}

You need to do the same for both the reading and the writing EntityManager configurations.

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