Override Properties file in Spring WebApp at Runtime

Question

I am loading properties file in my Spring WebApplication using PropertyPlaceholderConfigurer as below:

Answer 1

you just use in your application-context

<context:property-placeholder location="file:///${external.props}"
    order="-1" ignore-unresolvable="true" ignore-resource-not-found="true" />

problem is you just wrongly used location, actual location is vm arg variable key => ${external.props}

Answer 2

What I did to resolve the problem is, replaced the location attribute as ${ext.properties.dir:classpath:}/override.properties, as follows:

<context:property-placeholder
        location="${ext.properties.dir:classpath:}/override.properties" order="-1"
        ignore-unresolvable="true" ignore-resource-not-found="true" />

And supplied ext.properties.dir value from application-server/jvm as:

-Dext.properties.dir=file:/Users/ArpitAggarwal/properties/

Reference: 6-tips-for-managing-property-files-with-spring.

Answer 3

I think that working with multiple propertyPlaceholders is not a goog idea. I had a lot of problems when two xml configs, in the same context, loads each properties and they try cross-use them.

If you want to externalize a properties file, I would suggest a JNDI property:

<bean
    class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>classpath:db.properties</value>
            <value>classpath:mail.properties</value>
            <value>${java:com/env/myApp/externalProperties}
        </list>
    </property>
</bean>

Where the value of this JNDI would be: "file:/path-to-propertiesFile".

In this way you only need one propertyePlaceholder. Also note that by putting the external file as last location, if you have duplicate keys, spring will retain only the last one.