Using multiple DataSources in Spring and Hibernate

Question

I am having a main datasource, where I have read/write access and another datasource, where I just pull the data out and import it into my main datasource.

At the moment my whole application just uses the read/write database. Therefore, I configured it like that:

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:security="http://www.springframework.org/schema/security"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/aop
                        http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
                        http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-3.2.xsd
                        http://www.springframework.org/schema/tx
                        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">

    <context:annotation-config />

    <context:component-scan base-package="com.limitCalculator"
        annotation-config="true" />

    <tx:annotation-driven transaction-manager="transactionManager"
        proxy-target-class="true" />

    <bean id="mainGUI" class="com.limitCalculator.gui.scenarioSelection.MainWindow" />

    <!-- 1 Data Source -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="org.hsqldb.jdbcDriver" />
        <property name="url" value="jdbc:hsqldb:hsql://localhost/testDB" />
        <property name="username" value="sa" />
        <property name="password" value="" />
        <property name="initialSize" value="5" />
        <property name="maxActive" value="10" />
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="persistenceUnitName" value="jpaData" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
        </property>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.HSQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">false</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

    <bean id="entityManager"
        class="org.springframework.orm.jpa.support.SharedEntityManagerBean">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

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

    <!-- 2 Data Source -->
    <bean id="dataSource2" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="oracle.jdbc.OracleDriver" />
        <property name="url"
            value="jdbc:oracle:thin:@test.com.vi:1234:TEST" />
        <property name="username" value="test_db" />
        <property name="password" value="abcde" />
        <property name="maxActive" value="20" />
    </bean>
</beans>

My DAO Call:

@Component
public class SettingsDaoImpl {

    @Autowired
    @PersistenceContext    
    public EntityManager em;

    public SettingsDaoImpl() {
        super();
    }

    @Transactional
    public Long save(Settings sr)
    {
        em.persist(sr);
        return sr.getId();
    }

As you can see I added the second database in my application. However, I do not know how to properly call it inside my SettingsDaoImpl?

Any recommendations how to implement this in my current architecture.

Answer 1

您需要为每个数据源创建不同的实体管理器，并且需要在代码中定义@PersistenceContext的unitName属性以注入特定的实体管理器。