Accessing property value

[Niels Ull Harremoës]

Hi!

Often, I would like to use a specific property from a property file in my bean definition (using Spring 2.0.4).

If I use PropertyPlaceholderConfigurer, I will need to come up with a unique prefix/postfix, so as not to interfere with the rest of the configuration. This is not very encapsulated, and I may end up with a lot of $[], ${}, @[], @{}, #{}, #[] etc, if I need to do it several times. Can I scope the PropertyPlaceholderConfigurer to only process certain bean definitions?

Alternatively, I can use a MethodInvokingBeanFactory to call getProperty on the properties bean. But that is quite verbose (see the javadoc for MethodInvokingFactoryBean for a sample).

I ended up writing my own PropertyExtractorBeanFactory, to be used as:

<bean id="myKey" class="util.PropertyExtractorBeanFactory">
    <property name="properties">
        <util:properties id="myProps" location="props.properties"/>
    </property>
    <property name="key" value="myKey"/>
    <property name="defaultValue" value="myDefault"/>
</bean>

Is there a simpler approach, using the standard beans?

[wpoitras]

You can accomplish something similar with factory-bean/factory-method bean attributes:

<util:properties id="myProps" location="props.properties"/>
<bean id="myFile" factory-bean="myProps" factory-method="getProperty">
    <constructor-arg>myKey</constructor-arg>
    <constructor-arg>defaultValue</constructor-arg>
</bean>

I don't really see it as any shorter than yours. But at least you wouldn't need an additional class.