Spring-loading and injecting external properties into beans

Let's say you have a Spring managed bean that contains some properties that you would like to externalize from your application, say perhaps in a JBoss 'conf' folder properties file.  Apparently you can do this via annotations in Spring 3, but it's also fairly straightforward in Spring 2.5:

From the context.xml file:

    <bean id="propertyConfigurer"
          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="classpath:my_app.properties"/>
        <property name="placeholderPrefix" value="$prop{"/>
    </bean>
 
    <bean id="someBeanWithProps" class="my.class.with.Props">
        <property name="myPropA" value="$prop{prop.file.entry.prop.A}"/>
        <property name="myPropB" value="$prop{prop.file.entry.prop.B}"/>
    </bean>