package website.fedulov.routing.RoutingDataSource

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

public class RoutingDataSource extends AbstractRoutingDataSource {  
    @Override
    protected Object determineCurrentLookupKey() {
        return DbContextHolder.getDbType();
    }
}

public enum DbType {  
   MASTER,
   REPLICA1,
}

public class DbContextHolder {

   private static final ThreadLocal<DbType> contextHolder = new ThreadLocal<DbType>();

   public static void setDbType(DbType dbType) {
       if(dbType == null){
           throw new NullPointerException();
       }
      contextHolder.set(dbType);
   }

   public static DbType getDbType() {
      return (DbType) contextHolder.get();
   }

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

<bean id="dataSource" class="website.fedulov.routing.RoutingDataSource">  
 <property name="targetDataSources">
   <map key-type="com.sabienzia.routing.DbType">
     <entry key="MASTER" value-ref="dataSourceMaster"/>
     <entry key="REPLICA1" value-ref="dataSourceReplica"/>
   </map>
 </property>
 <property name="defaultTargetDataSource" ref="dataSourceMaster"/>
</bean>

<bean id="dataSourceMaster" class="org.apache.commons.dbcp.BasicDataSource">  
  <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
  <property name="url" value="${db.master.url}"/>
  <property name="username" value="${db.username}"/>
  <property name="password" value="${db.password}"/>
</bean>  
<bean id="dataSourceReplica" class="org.apache.commons.dbcp.BasicDataSource">  
  <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
  <property name="url" value="${db.replica.url}"/>
  <property name="username" value="${db.username}"/>
  <property name="password" value="${db.password}"/>
</bean>  

try{
      DbContextHolder.setDbType(DbType.REPLICA1);  
... 
    }  finally {
       DbContextHolder.clearDbType();              
    }