Spring+Hibernate实现动态SessionFactory切换

场景：

1）系统有多个数据库

2）且数据库类型也不尽相同

3）现在应用根据某些条件路由到具体的数据库

4）且在spring+hibernate框架下，支持依赖注入

已有实现，spring动态数据源，但无法实现动态SessionFactory，即不通数据库的方言不一样

目标：

在spring动态数据源的基础上，实现动态SessionFactory

1.配置多个数据源和SessionFactory，并给相应SessionFactory配置事务管理：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
    <!-- FOR SqlServer-->
    <bean id="SqlServer_DataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.microsoft.sqlserver.jdbc.SQLServerDriver" />
        <property name="url"
            value="url" />
        <property name="username" value="username" />
        <property name="password" value="password" />
    </bean>
    <bean id="SqlServer_SessionFactory"
        class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"
        p:mappingLocations="classpath:/com/entity/*.hbm.xml">
        <property name="dataSource" ref="SqlServer_DataSource" />
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.query.factory_class">org.hibernate.hql.ast.ASTQueryTranslatorFactory</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.SQLServer2008Dialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
            </props>
        </property>
    </bean>
    <bean id="SqlServer_TransactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="SqlServer_SessionFactory"/>
    </bean>

    <!-- FOR Oracle -->
    <bean id="Oracle _DataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="oracle.jdbc.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@localhost:1521/orcl" />
        <property name="username" value="username" />
        <property name="password" value="password" />
    </bean>
    <bean id="Oracle_SessionFactory"
        class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"
        p:mappingLocations="classpath:/com/entity/*.hbm.xml">
        <property name="dataSource" ref="Oracle_DataSource" />
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.query.factory_class">org.hibernate.hql.ast.ASTQueryTranslatorFactory</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
            </props>
        </property>
    </bean>
    <bean id="Oracle_TransactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="Oracle_SessionFactory"/>
    </bean>

</beans>

2. 为SessionFactory配置事务切面：

<tx:advice id="SqlServer_TxAdvice" transaction-manager="SqlServer_TransactionManager">
        <tx:attributes>
            <tx:method name="get*" read-only="true" />
            <tx:method name="find*" read-only="true" />
            <tx:method name="*" propagation="REQUIRED" rollback-for="Exception" />
        </tx:attributes>
    </tx:advice>
    <tx:advice id="Oracle_TxAdvice" transaction-manager="Oracle_TransactionManager">
        <tx:attributes>
            <tx:method name="get*" read-only="true" />
            <tx:method name="find*" read-only="true" />
            <tx:method name="*" propagation="REQUIRED" rollback-for="Exception" />
        </tx:attributes>
    </tx:advice>

    <aop:config proxy-target-class="true">
        <aop:pointcut id="txPointcut" expression="execution(* com.service.*.*(..))"/>
        <aop:advisor advice-ref="SqlServer_TxAdvice" pointcut-ref="txPointcut" order="1"/>
        <aop:advisor advice-ref="Oracle_TxAdvice" pointcut-ref="txPointcut" order="2"/>
    </aop:config>

3. 配置一个动态的SessionFactory：

<bean id="sessionFactory" class="com.DynamicSessionFactory"/>

4. 定义DynamicSessionFactory实现接口SessionFactory：

public class DynamicSessionFactory implements SessionFactory ,ApplicationContextAware{

    private static final long serialVersionUID = 1L;

    private ApplicationContext applicationContext;

    private SessionFactory getSessionFactory(String name) {
        return (SessionFactory) applicationContext.getBean(name);
    }
        //根据当前线程的SessionFactoryName获取SessionFactory
    private SessionFactory getSessionFactory() {
        return getSessionFactory(ThreadLocalUtil.
                .getSessionFactoryName());
    }

    public Reference getReference() throws NamingException {
        return getSessionFactory().getReference();
    }

    public Session openSession() throws HibernateException {
        return getSessionFactory().openSession();
    }

    public Session openSession(Interceptor interceptor)
            throws HibernateException {
        return getSessionFactory().openSession(interceptor);
    }

    public Session openSession(Connection connection) {
        return getSessionFactory().openSession(connection);
    }

    public Session openSession(Connection connection, Interceptor interceptor) {
        return getSessionFactory().openSession(connection,interceptor);
    }

    public Session getCurrentSession() throws HibernateException {
        return getSessionFactory().getCurrentSession();
    }

    public StatelessSession openStatelessSession() {
        return getSessionFactory().openStatelessSession();
    }

    public StatelessSession openStatelessSession(Connection connection) {
        return getSessionFactory().openStatelessSession(connection);
    }

    public ClassMetadata getClassMetadata(Class entityClass) {
        return getSessionFactory().getClassMetadata(entityClass);
    }

    public ClassMetadata getClassMetadata(String entityName) {
        return getSessionFactory().getClassMetadata(entityName);
    }

    public CollectionMetadata getCollectionMetadata(String roleName) {
        return getSessionFactory().getCollectionMetadata(roleName);
    }

    public Map getAllClassMetadata() {
        return getSessionFactory().getAllClassMetadata();
    }

    public Map getAllCollectionMetadata() {
        return getSessionFactory().getAllCollectionMetadata();
    }

    public Statistics getStatistics() {
        return getSessionFactory().getStatistics();
    }

    public void close() throws HibernateException {
        getSessionFactory().close();
    }

    public boolean isClosed() {
        return getSessionFactory().isClosed();
    }

    public Cache getCache() {
        return getSessionFactory().getCache();
    }

    public void evict(Class persistentClass) throws HibernateException {
        getSessionFactory().evict(persistentClass);
    }

    public void evict(Class persistentClass, Serializable id)
            throws HibernateException {
        getSessionFactory().evict(persistentClass, id);
    }

    public void evictEntity(String entityName) throws HibernateException {
        getSessionFactory().evictEntity(entityName);
    }

    public void evictEntity(String entityName, Serializable id)
            throws HibernateException {
        getSessionFactory().evictEntity(entityName, id);
    }

    public void evictCollection(String roleName) throws HibernateException {
        getSessionFactory().evictCollection(roleName);
    }

    public void evictCollection(String roleName, Serializable id)
            throws HibernateException {
        getSessionFactory().evictCollection(roleName, id);
    }

    public void evictQueries(String cacheRegion) throws HibernateException {
        getSessionFactory().evictQueries(cacheRegion);
    }

    public void evictQueries() throws HibernateException {
        getSessionFactory().evictQueries();
    }

    public Set getDefinedFilterNames() {
        return getSessionFactory().getDefinedFilterNames();
    }

    public FilterDefinition getFilterDefinition(String filterName)
            throws HibernateException {
        return getSessionFactory().getFilterDefinition(filterName);
    }

    public boolean containsFetchProfileDefinition(String name) {
        return getSessionFactory().containsFetchProfileDefinition(name);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext)
            throws BeansException {
        this.applicationContext = applicationContext;
    }    

}