Inject an external property into Spring context

Question

I have three apps in a Spring 2.5 managed project that share some code and differ in details.

Each application has a property (java.lang.String) which is used before the application context is built.

Building the app context takes some time and cannot happen first. As such, it's defined in each individual application. This property is duplicated in the context definition since it is also needed there. Can I get rid of that duplication?

Is it possible to inject that property into my application context?

Answer 1

Have a look at PropertyPlaceholderConfigurer.

The Spring documentation talks about it here.

<bean id="myPropertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="classpath:my-property-file.properties"/>
    <property name="placeholderPrefix" value="$myPrefix{"/>
</bean>

<bean id="myClassWhichUsesTheProperties" class="com.class.Name">
    <property name="propertyName" value="$myPrefix{my.property.from.the.file}"/>
</bean>

You then have reference to that String to anywhere you'd like in your application context, constructor-arg, property etc.