天猫购物券 翻倍:怎样用Hibernate配置多个数据源？

如果用xml配置的话，那就写两个配置文件，可以不再用“hibernate.cfg.xml”做文件名，随便什么都可以，像“mysql.cfg.xml”或“sqlserver.xml”都行。用Configuration类获取SessionFactory的代码：

SessionFactory mysqlFactory = new Configuration().configure("mysql.cfg.xml").buildSessionFactory();

SessionFactory sqlserverFactory = new Configuration().configure("sqlserver.xml").buildSessionFactory();

如果你用spring，多数据库就更简单了，像这段代码可以完成所有配置：

<beans>
<bean id="mysqlDS" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="url">
<value>jdbc:mysql://localhost:3306/test</value>
</property>
<property name="driverClassName">
<value>org.gjt.mm.mysql.Driver</value>
</property>
<property name="username">
<value>root</value>
</property>
<property name="password">
<value>123456</value>
</property>
</bean>

<bean id="mysqlFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource">
<ref local="mysqlDS"/>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
</props>
</property>
<property name="mappingResources">
<list>
<value>test.hbm.xml</value>
</list>
</property>
</bean>

<bean id="sqlserverDS" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="url">
<value>jdbc:odbc:test</value>
</property>
<property name="driverClassName">
<value>sun.jdbc.odbc.JdbcOdbcDriver</value>
</property>
<property name="username">
<value>root</value>
</property>
<property name="password">
<value>123456</value>
</property>
</bean>

<bean id="sqlserverFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource">
<ref local="sqlserverDS"/>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
</props>
</property>
<property name="mappingResources">
<list>
<value>test.hbm.xml</value>
</list>
</property>
</bean>

.......

</beans>

hibernate和spring还有很多可行的配置，可以参考他们的references，有很详细地说明的。

配置数据源

<!--本地库 -->
<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>java:comp/env/jdbc/bing</value>
</property>
</bean>

<!-- 用户中心库 -->
<bean id="dataSourceUser" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>java:comp/env/jdbc/user</value>
</property>
</bean>

<!-- SessionFactory配置 -->
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="packagesToScan" value="${application.domain.packages.bing}"/>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean>

<!--用户sessionFactory-->
<bean id="sessionFactoryUser" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSourceUser"/>
<property name="packagesToScan" value="${application.domain.packages.user}"/>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.SQLServer2005Dialect</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean>

<!--事务控制-->

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>

<bean id="transactionManagerUser" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactoryUser" />
</bean>

<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="insert*" rollback-for="Exception"/>
<tx:method name="save*" rollback-for="Exception"/>
<tx:method name="update*" rollback-for="Exception"/>
<tx:method name="remove*" rollback-for="Exception"/>
<tx:method name="delete*" rollback-for="Exception"/>
<tx:method name="add*" rollback-for="Exception"/>
<tx:method name="modify*" rollback-for="Exception"/>
<tx:method name="deploy*" rollback-for="Exception"/>
<tx:method name="*" read-only="true" rollback-for="Exception"/>
</tx:attributes>
</tx:advice>

<tx:advice id="txAdviceUser" transaction-manager="transactionManagerUser">
<tx:attributes>
<tx:method name="insert*" rollback-for="Exception"/>
<tx:method name="save*" rollback-for="Exception"/>
<tx:method name="update*" rollback-for="Exception"/>
<tx:method name="remove*" rollback-for="Exception"/>
<tx:method name="delete*" rollback-for="Exception"/>
<tx:method name="add*" rollback-for="Exception"/>
<tx:method name="modify*" rollback-for="Exception"/>
<tx:method name="deploy*" rollback-for="Exception"/>
<tx:method name="*" read-only="true" rollback-for="Exception"/>
</tx:attributes>
</tx:advice>

<aop:config proxy-target-class="true">
<aop:pointcut id="txPointcut" expression="execution(* *..*Service.*(..))" />
<aop:advisor advice-ref="txAdvice" pointcut-ref="txPointcut" />
<aop:advisor advice-ref="txAdviceUser" pointcut-ref="txPointcut" />
</aop:config>

正如一些传统的经典计算机文章大都会通过一个“hello,world”的例子开始讲解一样，我们也不例外，我们也将从一个相对简单的例子来阐述Hibernate的开发方法，但如果要真正阐述Hibernate的一些重要思想，仅仅靠在屏幕上打印一些字符是远远不够的，在我们的示例程序中，我们将创建一些对象，并将其保存在数据库中，然后对它们进行更新和查询。