程序是使用的是spring JdbcTemplate架构，简要记录下配置多数据源的方法：

1，设置数据源：

        在application.properties文件中配置多个数据源，示例中我配置了2个数据源，如下：

A、oracle

jdbc.driver=oracle.jdbc.OracleDriver
jdbc.url=jdbc:oracle:thin:@1localhost:1521:dev
jdbc.username=ling
jdbc.password=229

B、Mysql

#mysql
jdbc-mysql.driver=com.mysql.jdbc.Driver
jdbc-mysql.url=jdbc:mysql://localhost:3306/test
jdbc-mysql.username=root
jdbc-mysql.password=229 

2、配置applicationContext-dataSource.xml

        在applicationContext-dataSource.xml文件中获取数据源，程序使用的是jdbcTemplate架构，如下：

<!-- 数据源配置, oracle -->
<bean id="dataSource" class="org.apache.tomcat.jdbc.pool.DataSource" destroy-method="close">
    <!-- Connection Info -->
    <property name="driverClassName" value="${jdbc.driver}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />

    <!-- Connection Pooling Info -->
    <property name="maxActive" value="${jdbc.pool.maxActive}" />
    <property name="maxIdle" value="${jdbc.pool.maxIdle}" />
    <property name="minIdle" value="0" />
    <property name="defaultAutoCommit" value="false" />
</bean>

<!--mysql数据库，配置如下-->
<bean id="mysqlDataSource" class="org.apache.commons.dbcp.BasicDataSource">
   <property name="driverClassName" value="${jdbc-mysql.driver}" />
   <property name="url" value="${jdbc-mysql.url}" />
   <property name="username" value="${jdbc-mysql.username}" />
   <property name="password" value="${jdbc-mysql.password}" />

   <property name="maxActive" value="${jdbc.pool.maxActive}" />
   <property name="maxIdle" value="${jdbc.pool.maxIdle}" />
   <property name="minIdle" value="0" />
   <property name="defaultAutoCommit" value="false" />
</bean>

<!-- 动态数据引用类配置 -->
<bean id="dynamicDataSource" class="com.ffcs.itm.web.rocketmq.base.DynamicDataSource">
   <property name="targetDataSources">
      <map key-type="java.lang.String">
         <entry value-ref="dataSource" key="dataSource"></entry>
         <entry value-ref="mysqlDataSource" key="mysqlDataSource"></entry>
      </map>
   </property>
   <property name="defaultTargetDataSource" ref="dataSource">
   </property>
</bean>
 
 <!-- jdbcTemplate配置 -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
       <property name="dataSource">
      <ref bean="dynamicDataSource" />
   </property>
</bean>

 3，动态数据源类

        从步骤2中，可以看到使用了DynamicDataSource这个类，这是一个动态数据源类

A、DynamicDataSource

public class DynamicDataSource extends AbstractRoutingDataSource{ 
	@Override
	protected Object determineCurrentLookupKey() { 		    
        return CustomerContextHolder.getCustomerType();
	} 
}

B、CustomerContextHolder

public class CustomerContextHolder {
	public static final String DATA_SOURCE_ORACLE = "dataSource";// oracle 数据源 和  配置的 key 一样
	public static final String DATA_SOURCE_MYSQL = "mysqlDataSource";// mysql数据源和配置的key一样 	private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
	public static void setCustomerType(String customerType) {
		contextHolder.set(customerType);
	}

	public static String getCustomerType() {
		String dataSource = contextHolder.get();
		if (StringUtils.isEmpty(dataSource)) {
			return DATA_SOURCE_MYSQL;
		} else {
			return dataSource;
		}
	}

	public static void clearCustomerType() {
		contextHolder.remove();
	}

}

4，切换数据源

        建立service 切换数据源 最好在服务层切换

A、NodeMysqlService

@Service("nodeMysqlService") 
public class NodeMysqlService {
	   
	public String getMysqlCommandSeries() throws ApplicationException {
		NodeMysqlDao nodeMysqlDao = (NodeMysqlDao) ContextLoader.getCurrentWebApplicationContext().getBean("nodeMysqlDao");
		
		String commonSerials = "";
		try {
			CustomerContextHolder.setCustomerType(CustomerContextHolder.DATA_SOURCE_MYSQL); // 切换到mysql数据源

			commonSerials = nodeMysqlDao.getMysqlCommandSeries();
			
		} catch (Exception e) {
			e.printStackTrace();
			throw new ApplicationException(e.getMessage());
		}finally{
			CustomerContextHolder.clearCustomerType(); 
// 切换到默认数据源
		}
		return commonSerials;
	}

}

B、NodeMysqlDao:

@Component
public class NodeMysqlDao {

	private  String MYSQL_GET_SEQUENCE = "select branch_id as id fron branch";
	@Autowired
	private JdbcTemplate jdbcTemplate;


	public String getMysqlCommandSeries() throws ApplicationException, SystemException {

		String sequence = "";
		Map<String, Object> sequenceMap = new HashMap<String,Object>();

		try
		{
			sequenceMap = jdbcTemplate.queryForMap(MYSQL_GET_SEQUENCE);
			sequence = Long.toString((Long)sequenceMap.get("id")) ;

		} catch (Exception e){
			e.printStackTrace();
			System.out.println(e.getMessage());
		}

		return sequence;
	}

}

其它业务信息就自己建立。