Loading Liferay Properties from Spring IoC container (to get jdbc connection parameters) - spring

Question

I'm developing some portlets for Liferay Portal 5.2.3 with bundled tomcat 6.0.18 using Spring IoC container.
I need to map the User_ table used in Liferay database to an entity with Hibernate, so I need to use two different dataSources to separate the liferay db from the db used by portlets.
My jdbc.properties has to hold all connection parameters for both databases: no problem for the one used by portlets, but I am having issues determining which database uses liferay to hold its data.
My conclusion is that i should have something like this:
liferayConnection.url=jdbc:hsqldb:${liferay.home}/data/hsql/lportal
in order to get the database url dynamically loaded, according to Liferay properties found in portal-ext.properties. (Or, better, load the whole portal-ext.properties and read database properties from there).
The problem is that the placeholder is not resolved:
Caused by: org.springframework.beans.factory.BeanDefinitionStoreException: Invalid bean definition with name 'liferayDataSource' defined in class path resource [WEB-INF/applicationContext.xml]: Could not resolve placeholder 'liferay.home'
To dodge this problem I tried to load explicitly portal-ext.properties with a Spring bean:
<bean id="liferayPropertiesConfigurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
p:location="../../portal-ext.properties"/>
but no luck: liferay.home is not resolved but there aren't other errors.
How can I resolve the placeholder defined by Liferay? Thanks

Answer 1

You can use PropsUtil class (from Liferay) to get values of portal-ext.properties.
String value = PropsUtil.get("key");

Answer 2

For loading properties files from an applicationContext.xml file I usually use the PropertiesFactoryBean specifying the location property with a the name of the file located in the classpath, like this:
<bean name="myHibernateProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="location">
<value>classpath:hibernate.properties</value>
</property>
</bean>
Make sure the properties files are in a folder/package that is in the classpath.

Answer 3

You can call PropsUtil using SpringEL. for example:
#{T(com.liferay.portal.kernel.util.PropsUtil).get('liferay.home')}
I haven't tried exactly this. but you could load the liferay properties that you need with the following:
<util:properties id="liferayProps">
<prop key="liferay.home">#{T(com.liferay.portal.kernel.util.PropsUtil).get('liferay.home')}</prop>
</util:properties>