Connect J2EE application with two different databases

Question

I am developping J2EE application with appfuse that have default settings with mySQL

<!-- Database settings -->
<dbunit.dataTypeFactoryName>org.dbunit.ext.mysql.MySqlDataTypeFactory</dbunit.dataTypeFactoryName>
<dbunit.operation.type>CLEAN_INSERT</dbunit.operation.type>
<hibernate.dialect>org.hibernate.dialect.MySQL5InnoDBDialect</hibernate.dialect>
<jdbc.groupId>mysql</jdbc.groupId>
<jdbc.artifactId>mysql-connector-java</jdbc.artifactId>
<jdbc.version>5.1.27</jdbc.version>
<jdbc.driverClassName>com.mysql.jdbc.Driver</jdbc.driverClassName>
<jdbc.url>jdbc:mysql://localhost/${db.name}?createDatabaseIfNotExist=true&amp;amp;useUnicode=true&amp;amp;characterEncoding=utf-8&amp;amp;autoReconnect=true</jdbc.url>
<jdbc.username>root</jdbc.username>
<jdbc.password></jdbc.password>
<jdbc.validationQuery>SELECT 1 + 1</jdbc.validationQuery>

But i need to connect my application with external database (SQL QERVER)to retreive some data. I need help to configure maven to use two different database (mysql +sql server)

Answer 1

maven will help you out with loading of the driver jar files. You would be creating two data source / session factory to achieve this.

Answer 2

I think this can be achieved quite easily in a brief guideline as follows:

1. Create a second "dataSource" bean definition in applicationContext-resources.xml with MSSQL specific values such as driver class, url etc. Give it a different bean id, "dataSourceMSSQL" perhaps. Bind them up to different properties file if you don't want to hard coded property values. For simplicity you can just hard coded it (not recommended).
   
   If you chose otherwise, you need to create another properties file to store mssql connection properties, perhaps jdbc-mssql.properties and add it into propertyConfigurer list. This also require you to make changes to your pom file to include custom settings under <!-- Database settings --> section. This can be a bit complicated.

2. Create another "sessionFactory" bean definition in applicationContext-dao.xml with MSSQL specific values such as hibernate dialect etc. and binds it to "dataSourceMSSQL" as dataSource property ref. Give it a different bean id perhaps, "sessionFactoryMSSQL".

3. Wire your DAOs which require the new sessionFactory i.e.:

@Autowired
private SessionFactory sessionFactoryMSSQL;

Hope that will work for you.