First of all, add a bean in spring's configuration files like this:
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderconfigurer">
<property name="locations">
<list>
<value>...property files</value>
</list>
</property>
</bean>
Put the property files under classpath, then you can use ${property name} to reference properties in your property files in your spring configuration files.
Also, system properties and properties sent it by -D are also available through ${property name}.