使用Spring + Hibernate + JPA的多个数据库

Question

我正在尝试配置Spring + Hibernate + JPA来处理两个数据库(MySQL和MSSQL).

我的datasource-context.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:aop="http://www.springframework.org/schema/aop"
 xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
  http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
  http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd
  http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd"
 xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
 xmlns:util="http://www.springframework.org/schema/util">

 <!--
 Data Source config 
  -->
 <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
  destroy-method="close" p:driverClassName="${local.jdbc.driver}" p:url="${local.jdbc.url}"
  p:username="${local.jdbc.username}" p:password="${local.jdbc.password}">
 </bean>

 <bean id="dataSourceRemote" class="org.apache.commons.dbcp.BasicDataSource"
  destroy-method="close" p:driverClassName="${remote.jdbc.driver}"
  p:url="${remote.jdbc.url}" p:username="${remote.jdbc.username}"
  p:password="${remote.jdbc.password}" />

 <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"
  p:entity-manager-factory-ref="entityManagerFactory" />

 <!-- 
    JPA config   
    -->
 <tx:annotation-driven transaction-manager="transactionManager" />

 <bean id="persistenceUnitManager"
  class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
        <property name="persistenceXmlLocations">
   <list value-type="java.lang.String">
    <value>classpath*:config/persistence.local.xml</value>
    <value>classpath*:config/persistence.remote.xml</value>
   </list>
  </property>

  <property name="dataSources">
   <map>
    <entry key="localDataSource" value-ref="dataSource" />
    <entry key="remoteDataSource" value-ref="dataSourceRemote" />
   </map>
  </property>
  <property name="defaultDataSource" ref="dataSource" />
 </bean>

 <bean id="entityManagerFactory"
  class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
  <property name="jpaVendorAdapter">
   <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
    p:showSql="true" p:generateDdl="true">
   </bean>
  </property>
  <property name="persistenceUnitManager" ref="persistenceUnitManager" />
<property name="persistenceUnitName" value="localjpa"/>
 </bean>

 <bean
  class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

</beans>

每个persistence.xml包含一个单元,如下所示:

<persistence-unit name="remote" transaction-type="RESOURCE_LOCAL">
  <properties>
   <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.DefaultNamingStrategy" />
   <property name="hibernate.dialect" value="${remote.hibernate.dialect}" />
   <property name="hibernate.hbm2ddl.auto" value="${remote.hibernate.hbm2ddl.auto}" />
  </properties>
 </persistence-unit>

PersistenceUnitManager导致以下异常:

设置bean属性'persistenceUnitManager'时,无法解析对bean'persistenceUnitManager'的引用; 嵌套异常是org.springframework.beans.factory.BeanCreationException:在类路径资源[config/datasource-context.xml]中定义名称为'persistenceUnitManager'的bean时出错:bean的初始化失败; 嵌套异常是org.springframework.beans.TypeMismatchException:无法将类型[java.util.ArrayList]的属性值转换为属性'persistenceXmlLocation'的必需类型[java.lang.String]; 嵌套异常是java.lang.IllegalArgumentException:无法将类型[java.util.ArrayList]的值转换为属性'persistenceXmlLocation'所需的类型[java.lang.String]:找不到匹配的编辑器或转换策略

如果只留下一个没有列表的persistence.xml,每个都可以正常工作,但我需要2个单元......

我也试图找到在Spring + Hibernate上下文中使用两个数据库的替代解决方案,所以我将不胜感激任何解决方案.

更改为persistenceXmlLocations以下后出现新错误:

{classpath:config/persistence.local.xml,classpath:config/persistence.remote.xml}中没有定义单个默认持久性单元

更新:

我添加了persistenceUnitName,它可以工作,但只有一个单元,仍然需要帮助.

更新:

我更改了配置文件:datasource-context.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:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd"
    xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:util="http://www.springframework.org/schema/util">

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close" p:driverClassName="${local.jdbc.driver}" p:url="${local.jdbc.url}"
        p:username="${local.jdbc.username}" p:password="${local.jdbc.password}">
    </bean>

    <bean id="dataSourceRemote" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close" p:driverClassName="${remote.jdbc.driver}"
        p:url="${remote.jdbc.url}" p:username="${remote.jdbc.username}"
        p:password="${remote.jdbc.password}">
    </bean>

    <bean
        class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor">
        <property name="defaultPersistenceUnitName" value="pu1" />
    </bean>

    <bean id="persistenceUnitManager"
        class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
        <property name="persistenceXmlLocation" value="${persistence.xml.location}" />
        <property name="defaultDataSource" ref="dataSource" /> <!-- problem -->
        <property name="dataSources">
            <map>
                <entry key="local" value-ref="dataSource" />
                <entry key="remote" value-ref="dataSourceRemote" />
            </map>
        </property>
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
                p:showSql="true" p:generateDdl="true">
            </bean>
        </property>
        <property name="persistenceUnitManager" ref="persistenceUnitManager" />
        <property name="persistenceUnitName" value="pu1" />
        <property name="dataSource" ref="dataSource" />
    </bean>

    <bean id="entityManagerFactoryRemote"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
                p:showSql="true" p:generateDdl="true">
            </bean>
        </property>
        <property name="persistenceUnitManager" ref="persistenceUnitManager" />
        <property name="persistenceUnitName" value="pu2" />
        <property name="dataSource" ref="dataSourceRemote" />
    </bean>

    <tx:annotation-driven />

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"
        p:entity-manager-factory-ref="entityManagerFactory" />


    <bean id="transactionManagerRemote" class="org.springframework.orm.jpa.JpaTransactionManager"
        p:entity-manager-factory-ref="entityManagerFactoryRemote" />

</beans>

persistence.xml中

<?xml version="1.0" encoding="UTF-8"?>
<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_1_0.xsd"
    version="1.0">

    <persistence-unit name="pu1" transaction-type="RESOURCE_LOCAL">
        <properties>
            <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.DefaultNamingStrategy" />
            <property name="hibernate.dialect" value="${local.hibernate.dialect}" />
            <property name="hibernate.hbm2ddl.auto" value="${local.hibernate.hbm2ddl.auto}" />                          
        </properties>
    </persistence-unit>

    <persistence-unit name="pu2" transaction-type="RESOURCE_LOCAL">
        <properties>
            <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.DefaultNamingStrategy" />
            <property name="hibernate.dialect" value="${remote.hibernate.dialect}" />
            <property name="hibernate.hbm2ddl.auto" value="${remote.hibernate.hbm2ddl.auto}" />
        </properties>
    </persistence-unit>

</persistence>

现在它构建了两个entityManagerFactory,但它们都是用于Microsoft SQL Server

[main] INFO org.hibernate.ejb.Ejb3Configuration - Processing PersistenceUnitInfo [
    name: pu1
    ...]
[main] INFO org.hibernate.cfg.SettingsFactory - RDBMS: Microsoft SQL Server

[main] INFO org.hibernate.ejb.Ejb3Configuration - Processing PersistenceUnitInfo [
    name: pu2
    ...]
[main] INFO org.hibernate.cfg.SettingsFactory - RDBMS: Microsoft SQL Server (but must MySQL)

我建议,只使用dataSource,dataSourceRemote(无替换)不起作用.那是我的最后一个问题.

Answer 1

你需要使用persistenceXmlLocations属性(注意复数)而不是persistenceXmlLocation.它是一个字符串数组,因此它将从列表中自动转换:

<bean id="persistenceUnitManager"
      class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
  <property name="persistenceXmlLocations"><list>
    <value>classpath*:config/persistence.local.xml</value>
    <value>classpath*:config/persistence.remote.xml</value>
  </list></property>
  ...

更新(基于编辑)

您entityManagerFactory没有指定persistenceUnitName属性.您必须明确这样做,因为您要定义多个持久性单元并且entityManagerFactory必须知道要使用哪个持久性单元.

Answer 2

贾斯汀,3号可以用更标准的方式完成,如下所示:

1. 在你的Spring上下文中:

   <context:annotation-config />
   

2. 在Spring管理的DAO中(注意unitName属性):

   @PersistenceContext(unitName = "pu1"`) protected EntityManager entityManager;
   

这样,对应于名为"pu1"的持久性单元的正确实例化的EntityManager将被注入相应的DAO中.

Answer 3

如果您按照本教程 http://www.javacodegeeks.com/2010/05/jboss-42x-spring-3-jpa-hibernate.html进行以下更改,则可以访问两个不同的数据库:

1. persistence.xml,为您的第二个数据库定义第二个pesristence-unit.
2. spring.xml,在不同的名称下定义第二个entityManagerFactory bean,让我们说"entityManagerFactoryDB2"并将其配置为使用第二个数据库的持久单元.

3. 对于您要访问第二个数据库的每个DAO,包括以下内容:

   @Autowired
   private EntityManagerFactory entityManagerFactoryDB2;
   
   @PostConstruct
   public void init() {
       super.setEntityManagerFactory(entityManagerFactoryDB2);
   }
   

就这样!

在Spring服务类上,像往常一样使用DAO!