package lhp.example.context;
public enum DBType {
      dataSource1, dataSource2;
}

package lhp.example.context;

public class ContextHolder {
    private static final ThreadLocal<Object> holder = new ThreadLocal<Object>();

    public static void setDbType(DBType dbType) {
        holder.set(dbType);
    }

    public static DBType getDbType() {
        return (DBType) holder.get();
    }

    public static void clearDbType() {
        holder.remove();
    }
}

package lhp.example.context;

import java.util.logging.Logger;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {
    public static final Logger logger = Logger.getLogger(DynamicDataSource.class.toString());

    @Override
    protected Object determineCurrentLookupKey() {
        DBType key = ContextHolder.getDbType();//获得当前数据源标识符
        //logger.info("当前数据源 :" + key);
        return key;
    }

}

<!-- 数据源1 ： mysql -->
    <bean id="dataSource1" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mysql://127.0.0.1:3306/dec" />
        <property name="user" value="root" />
        <property name="password" value="" />
    </bean>
    <!-- 数据源2 ： mysql  -->
    <bean id="dataSource2" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mysql://127.0.0.1:3306/lms" />
        <property name="user" value="root" />
        <property name="password" value="" />
    </bean>

    <!-- 数据源3 ：  access -->
    <bean id="dataSource3" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="sun.jdbc.odbc.JdbcOdbcDriver" />
        <property name="jdbcUrl" value="jdbc:odbc:accessTest" />
        <property name="user" value="administrator" />
        <property name="password" value="XLZX0309" />
    </bean>

    <!-- mysql 动态数据源设置-->
    <bean id="mysqlDynamicDataSource" class="lhp.example.context.DynamicDataSource">
        <property name="targetDataSources">
            <!-- 标识符类型 -->
            <map key-type="lhp.example.context.DBType">
                <entry key="dataSource1" value-ref="dataSource1" />
                <entry key="dataSource2" value-ref="dataSource2" />
            </map>
        </property>
        <property name="defaultTargetDataSource" ref="dataSource1" />
    </bean>
    

<!-- mysql sessionFactory -->
    <bean id="mysqlSessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="dataSource" ref="mysqlDynamicDataSource" />
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop><!--create validate -->
                <prop key="hibernate.query.substitutions">true 1, false 0</prop>
            </props>
        </property>
    </bean>
    
    <!-- access sessionFactory -->
    <bean id="aceessSessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource3" />
        <property name="hibernateProperties">
            <props>
                <!-- access 语法和MSSQL相似 所以用的MSSQL方言，或者可以使用第三方方言 -->
                <prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
                <prop key="hibernate.jdbc.batch_size">30</prop>
                <prop key="hibernate.jdbc.fetch_size">50</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">false</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop><!--create validate -->
                <prop key="hibernate.query.substitutions">true 1, false 0</prop>
                <prop key="hibernate.cglib.use_reflection_optimizer">true</prop>
                <!-- <prop key="hibernate.cache.use_second_level_cache">true</prop> -->
                <!-- <prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop> -->
                <!-- <prop key="hibernate.cache.use_query_cache">true</prop> -->
                <!-- <prop key="hibernate.generate_statistics">true</prop> -->
                <!-- <prop key="hibernate.cache.provider_configuration_file_resource_path">classpath:ehcache.xml</prop> -->
            </props>
        </property>
    </bean>

package lhp.example.junit;

import static org.junit.Assert.*;
import java.sql.DatabaseMetaData;
import lhp.example.context.ContextHolder;
import lhp.example.context.DBType;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ServiceTest {
    private ApplicationContext context;
    //三个数据源的URL
    private String dataSource1_URL = "jdbc:mysql://127.0.0.1:3306/dec";
    private String dataSource2_URL = "jdbc:mysql://127.0.0.1:3306/lms";
    private String dataSource3_URL = "jdbc:odbc:accessTest";
    private SessionFactory mysqlSessionFactory;
    private SessionFactory aceessSessionFactory;

    @Before
    public void setUp() throws Exception {
        // 选择数据源初始化spring
        ContextHolder.setDbType(DBType.dataSource1);
        //
        String[] xmlFiles = new String[] { 
                "applicationContext-dataSource.xml",
                "applicationContext-hibernate.xml",
                "applicationContext-spring.xml" };
        //
        context = new ClassPathXmlApplicationContext(xmlFiles);
        //
        mysqlSessionFactory = (SessionFactory) context.getBean("mysqlSessionFactory");
        aceessSessionFactory = (SessionFactory) context.getBean("aceessSessionFactory");
    }

    @SuppressWarnings("deprecation")
    @Test
    public void mysqlDataSourceTest() {
        try {

            Session mysqlSession = mysqlSessionFactory.openSession();
            // 获得数据库元数据
            DatabaseMetaData meatData = mysqlSession.connection().getMetaData();

            // 默认启动数据源 dataSource1
            //断言当前数据源URL是否是dataSource1的URL
            assertEquals(dataSource1_URL, meatData.getURL());

            // 切换到数据源 dataSource2
            ContextHolder.setDbType(DBType.dataSource2);
            mysqlSession = mysqlSessionFactory.openSession();
            meatData = mysqlSession.connection().getMetaData();
            //断言当前数据源URL是否是dataSource2的URL
            assertEquals(dataSource2_URL, meatData.getURL());

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    @SuppressWarnings("deprecation")
    @Test
    public void accessDataSourceTest() {
        try {
            Session accessSession = aceessSessionFactory.openSession();
            // 获得数据库元数据
            DatabaseMetaData meatData = accessSession.connection().getMetaData();
            //断言当前数据源URL是否是dataSource3的URL
            assertEquals(dataSource3_URL, meatData.getURL());


        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}