Is it possible to have multiple PropertyPlaceHolderConfigurer in my applicationContext?

Question

I need to load a specific applicationContext.xml file according to a given system property. This itself loads a file with the actual configuration. Therefore I need two PropertyPlaceHolderConfigurer, one which resolves the system param, and the other one within the actual configuration.

Any ideas how to do this?

Answer 1

Yes you can do more than one. Be sure to set ignoreUnresolvablePlaceholders so that the first will ignore any placeholders that it can't resolve.

<bean id="ppConfig1" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
   <property name="ignoreUnresolvablePlaceholders" value="true"/>
   <property name="locations">
    <list>
             <value>classpath*:/my.properties</value>
    </list>
  </property>
</bean>

<bean id="ppConfig2" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
   <property name="ignoreUnresolvablePlaceholders" value="false"/>
   <property name="locations">
    <list>
             <value>classpath*:/myOther.properties</value>
    </list>
  </property>
</bean>

Depending on your application, you should investigate systemPropertiesMode, it allows you to load properties from a file, but allow the system properties to override values in the property file if set.

Answer 2

Another solution is to use placeholderPrefix property of PropertyPlaceholderConfigurer. You specify it for the second (third, fourth...) configurer, and then prefix all your corresponding placeholders, thus there will be no conflict.

<bean id="mySecondConfigurer"
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
        p:location="classpath:/myprops.properties" 
        p:placeholderPrefix="myprefix-"/>

<bean class="com.mycompany.MyClass" p:myprop="${myprefix-value.from.myprops}"/>

Answer 3

Beware -- there might be a bug related to multiple configurers. See http://jira.spring.io/browse/SPR-5719 for more details.

I'm unable to get multiple to work locally... but I'm not yet blaming anyone but myself.