<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"> 
    <property name="driverClassName" value="net.sourceforge.jtds.jdbc.Driver"> 
    </property> 
    <property name="url" value="jdbc:jtds:sqlserver://10.82.81.51:1433;databaseName=standards"> 
    </property> 
    <property name="username" value="youguess"></property> 
    <property name="password" value="youguess"></property> 
  </bean> 
  <bean id="dataSource2" class="org.apache.commons.dbcp.BasicDataSource"> 
    <property name="driverClassName" value="net.sourceforge.jtds.jdbc.Driver"> 
    </property> 
    <property name="url" value="jdbc:jtds:sqlserver://10.82.81.52:1433;databaseName=standards"> 
    </property> 
    <property name="username" value="youguess"></property> 
    <property name="password" value="youguess"></property> 
</bean> 

package com.standard.core.util; 
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; 
public class DynamicDataSource extends AbstractRoutingDataSource { 
  @Override 
  protected Object determineCurrentLookupKey() { 
    return CustomerContextHolder.getCustomerType(); 
  } 
} 

package com.standard.core.util; 
public class CustomerContextHolder { 
  public static final String DATA_SOURCE_A = "dataSource"; 
  public static final String DATA_SOURCE_B = "dataSource2"; 
  private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>(); 
  public static void setCustomerType(String customerType) { 
    contextHolder.set(customerType); 
  } 
  public static String getCustomerType() { 
    return contextHolder.get(); 
  } 
  public static void clearCustomerType() { 
    contextHolder.remove(); 
  } 
} 

<bean id="dynamicDataSource" class="com.standard.core.util.DynamicDataSource" > 
    <property name="targetDataSources"> 
      <map key-type="java.lang.String"> 
        <entry value-ref="dataSource" key="dataSource"></entry> 
        <entry value-ref="dataSource2" key="dataSource2"></entry> 
      </map> 
    </property> 
    <property name="defaultTargetDataSource" ref="dataSource" > 
    </property> 
  </bean>