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javaspringservlets
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Reputation: 13485

Can one Spring PropertyPlaceholderConfigurer configure another one?

I have a PropertyPlaceholderConfigurer like this:

<bean id="propertyPlaceholderConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="ignoreUnresolvablePlaceholders" value="true"/>
    <property name="locations">
        <list>
            <value>classpath:assuredlabor/margarita-${runningMode}.properties</value>
        </list>
    </property>
</bean>

I would like to be able to specify my running mode in web.xml like this:

<context-param>
    <param-name>runningMode</param-name>
    <param-value>production</param-value>
</context-param>

So I put this bean ABOVE the 'main' property bean I described above:

<bean id="servletPropertyPlaceholderConfigurer" class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer">
</bean>

But that doesn't seem to work.

Is this possible with Spring? I am using version 2.5 right now.

I found this similar question:

PropertyPlaceholderConfigurer with Tomcat & ContextLoaderListener

But there is no discussion of the ServletContextPropertyPlaceholderConfigurer, so I think it is a legitimate question.

Upvotes: 0

Views: 2332

Answers (2)

Matt
Matt

Reputation: 11805

You can't do this in spring 2, without some custom coding I don't think, since one property placeholder cannot configure another.

You need to use spring 3 to get this out of the box. To accomplish this, you have to create a bean that somehow has the value you want, and use spring-el to reference that spring when setting up your property placeholder. There's a special bean for getting individual servlet context parameters as show below:

<bean id="runningMode" class="org.springframework.web.context.support.ServletContextAttributeFactoryBean">
  <property name="attributeName" value="runningMode" />
</bean>

<bean id="propertyPlaceholderConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="ignoreUnresolvablePlaceholders" value="true"/>
    <property name="locations">
        <list>
            <value>classpath:assuredlabor/margarita-#{runningMode}.properties</value>
        </list>
    </property>
</bean>

And then you can just refer to any of the properties in the normal ${} syntax

Upvotes: 1

gpeche
gpeche

Reputation: 22514

From the source code:

Subclass of PropertyPlaceholderConfigurer that resolves placeholders as ServletContext init parameters (that is, web.xml context-param entries).

Can be combined with "locations" and/or "properties" values in addition to web.xml context-params. Alternatively, can be defined without local properties, to resolve all placeholders as web.xml context-params (or JVM system properties).

If a placeholder could not be resolved against the provided local properties within the application, this configurer will fall back to ServletContext parameters. Can also be configured to let ServletContext init parameters override local properties (contextOverride=true).

Optionally supports searching for ServletContext attributes: If turned on, an otherwise unresolvable placeholder will matched against the corresponding ServletContext attribute, using its stringified value if found. This can be used to feed dynamic values into Spring's placeholder resolution.

If not running within a WebApplicationContext (or any other context that is able to satisfy the ServletContextAware callback), this class will behave like the default PropertyPlaceholderConfigurer. This allows for keeping ServletContextPropertyPlaceholderConfigurer definitions in test suites.

As I understand it, that implies that you can use just a single configurer:

<bean id="propertyPlaceholderConfigurer" class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer">
    <property name="ignoreUnresolvablePlaceholders" value="true"/>
    <property name="locations">
        <list>
            <value>classpath:assuredlabor/margarita-${runningMode}.properties</value>
        </list>
    </property>
</bean>

Upvotes: 1

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