从具有相同持久性单元的多个Db读取？

Question

我需要一些帮助来使用相同的Persistence单元为多个db配置多个连接.

它们都具有相同的架构.因此,我想使用相同的持久性单元/ DAO等,并且不想设置10个EntityManagers,10 Persistence xml等.有没有办法做到这一点？这是我当前的配置:

  <persistence-unit name="PersistenceUnit-c1" transaction-type="RESOURCE_LOCAL">
        <properties>
            <property name="hibernate.show_sql" value="${hibernate-show-sql}"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.SybaseDialect" />
            <property name="hibernate.c3p0.min_size" value="${hibernate-c3p0-min-size}" />
            <property name="hibernate.c3p0.max_size" value="${hibernate-c3p0-max-size}" />
            <property name="hibernate.c3p0.timeout" value="${hibernate-c3p0-timeout}" />
            <property name="hibernate.c3p0.max_statements" value="${hibernate-c3p0-max-statements}" />
            <property name="hibernate.c3p0.idle_test_period" value="${hibernate-c3p0-idle-test-periods}" />     
        </properties>

        <class>com.domain.TktOrder</class>
        <exclude-unlisted-classes/>
    </persistence-unit>

我也使用Spring/hibernate来设置我的上下文:

    <bean id="EntityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    p:persistenceUnitName="PersistenceUnit-c1" 
    p:dataSource-ref="DataSource">
    <property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
            p:showSql="${hibernate-show-sql}" 
            p:generateDdl="false" 
            p:databasePlatform="org.hibernate.dialect.SybaseDialect" />
    </property>
    <property name="loadTimeWeaver">
        <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" />
    </property>
</bean>

<bean id="DataSource" 
    class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close" 
    p:driverClass="net.sourceforge.jtds.jdbc.Driver"
    p:jdbcUrl="jdbc:jtds:sybase://url.net:port;DatabaseName=db_1"
    p:user="user" 
    p:password="password"
    />

最后我使用:

@PersistenceContext(unitName="PersistenceUnit-c1")
public void setEntityManager(EntityManager entityManager)
{
    this.entityManager = entityManager;     

}

将我的EntityManager注入我的DAO

如何扩展此模型以便能够使用db1然后更改数据源并再次执行db2等？

非常感谢提前帮助!

Answer 1

经过几次尝试,我找到了一个似乎符合要求的解决方案.

请先看一下:dynamic-datasource-routing

这使用了一些您需要的自定义类,键类是AbstractRoutingDataSource.

这样重新配置我的数据源bean,如下所示:

    <bean id="dataSource" class="com.domain.etc.etc.recon.utils.RoutingDataSource">
    <property name="targetDataSources">
        <map key-type="com.domain.etc.etc.recon.utils.DbType">
            <entry key="C1" value-ref="C1" />
            <entry key="C2" value-ref="C2" />
        </map>
    </property>
    <property name="defaultTargetDataSource" ref="C3" />
</bean>

连接一个C1,C2看起来像:

    <bean id="parentDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"
    abstract="true">
    <property name="driverClassName" value="net.sourceforge.jtds.jdbc.Driver" />
    <property name="username" value="*******" />
    <property name="password" value="*******" />
</bean>

<bean id="C1" parent="parentDataSource">
    <property name="url" 
        value="jdbc:jtds:sybase://URL:PORT;DatabaseName=dbname" />
</bean>

<bean id="C2" parent="parentDataSource">
    <property name="url"
        value="jdbc:jtds:sybase://URL:PORT;DatabaseName=dbname2" />
</bean>

<bean id="C3" parent="parentDataSource">
    <property name="url"
        value="jdbc:jtds:sybase://URL:PORT;DatabaseName=dbname3" />
</bean>

你可以像原来的问题一样将它注入EntityManager;

    <bean id="EntityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    p:persistenceUnitName="PersistenceUnit" 
    p:dataSource-ref="dataSource">
    <property name="persistenceXmlLocation" value="classpath:META-INF/persistence-.xml" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
            p:showSql="${hibernate-show-sql}" 
            p:generateDdl="false" 
            p:databasePlatform="org.hibernate.dialect.SybaseDialect" />
    </property>
    <property name="loadTimeWeaver">
        <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" />
    </property>
</bean>

在此之后,您需要在上面的链接中使用您自己的java类实现,以便能够在数据源之间切换.这只不过是将类重命名为对您来说更有意义的类.将Enum链接到C1,C2,C3等,最后指向你自己的dao来完成工作.

祝好运!