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Multiple Database

Krishnakumar Ramanathan

Joined: Aug 04, 2008
Posts: 6
Hi all,

I need to switch databases at run time, in my application user is allowed to choose the database from the list of databases, I try to use AbstractRoutingDataSource

this is my java class which sets the new Database

package com.ncsts.view.bean;

import org.springframework.util.Assert;

public class ChangeContextHolder {
public enum DataBaseType {


private static final ThreadLocal<DataBaseType> contextHolder =
new ThreadLocal<DataBaseType>();
public static void setDataBaseType(DataBaseType dataBaseType) {
Assert.notNull(dataBaseType, "DataBaseType cannot be null");

public static DataBaseType getDataBaseType() {
return (DataBaseType)contextHolder.get();


public static void clearDataBase() {

this is my class which extends AbstractRoutingDataSource

package com.ncsts.view.bean;

import java.util.Map;

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

public class RoutingDataSource extends AbstractRoutingDataSource{
private Map targetDataSources;
private Object defaultTargetDataSource;

protected Object determineCurrentLookupKey() {
return ChangeContextHolder.getDataBaseType();


this is my context.xml file

<bean id="parentDataSource"
<property name="driverClassName" value="${db.driverClassName}"></property>
<property name="username" value="${db.1.username}"></property>
<property name="password" value="${db.1.password}"></property>
<bean id="db3DataSource" parent="parentDataSource">
<property name="url" value="${db.1.url}"></property>
<bean id="db2DataSource" parent="parentDataSource">
<property name="url" value="${db.2.url}"></property>

<bean id="dataSource"
<property name="targetDataSources">
<entry key="com.ncsts.view.bean.ChangeContextHolder.DataBaseType.DEMO1"
value-ref="db3DataSource" />
value-ref="db2DataSource" />
<property name="defaultTargetDataSource" ref="db2DataSource" />

can anybody help me to point out where I am going wrong
Vinod K Singh
Ranch Hand

Joined: Sep 30, 2008
Posts: 198
From your message it is not clear, what problem you are facing. Also formatting the code will increase the readability and people will be able to help you out.

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Marc Peabody
pie sneak

Joined: Feb 05, 2003
Posts: 4727

What are you trying to accomplish with ThreadLocal? If this is for a web application, I don't think this class will behave the way you're expecting.

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subject: Multiple Database