带有Spring PropertyPlaceholderConfigurer属性标志的IllegalArgumentException

Question

In my app I am using SpringBoot and the Spring Batch(and admin) frameworks. I am also using an application.yaml file to store all of the Properties I need. I am having trouble with Properties because there is a PropertyPlaceholderConfigurer bean created in SpringBatchAdmin that has the flag ignoreUnresolvablePlaceholders set to false . Here is the aforementioned bean:

<bean id="placeholderProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath:/org/springframework/batch/admin/bootstrap/batch.properties</value>
                <value>classpath:batch-default.properties</value>
                <value>classpath:batch-${ENVIRONMENT:hsql}.properties</value>
            </list>
        </property>
        <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
        <property name="ignoreResourceNotFound" value="true" />
        <property name="ignoreUnresolvablePlaceholders" value="false" />
        <property name="order" value="1" />
    </bean>

My problem is that currently Spring searches in these 3 files to read ALL OF the properties that are fetched using the @Value annotation. So what happens is that I have other dependencies that have declared their own Properties and Spring is forcing me to put these Properties inside one of the 3 files declared in the PropertyPlaceholderConfigurer bean created in SpringBatchAdmin.

So, for example, the following class/bean:

@Component
public class Example{
   @Value("${find.me}")
   private String findMe;

   ...
}

will have to look in the following 3 files:

batch.properties 
batch-default.properties 
batch-sqlserver.properties

and if the property find.me is not in one of these files, then I get the following exception:

java.lang.IllegalArgumentException: Could not resolve placeholder 'find.me' in string value "${find.me}"

I want to add that the problem DOES NOT come from using yaml or Spring not finding the "find.me" property, since if I don't use SpringBatchAdmin that creates the PropertyPlaceholderConfigurer the property "find.me" is effectively found in my application.yaml file.

Also, I cannot modify the PropertyPlaceholderConfigurer in question because it comes from an external source(not mine, but SpringBatchAdmin).

How can I solve this?

Answer 1

You can try defining a BeanPostProcessor component that sets the ignoreUnresolvablePlaceholders field to true after the PropertyPlaceholderConfigurer bean has been created:

@Component
class PropertyPlaceholderConfig extends BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof PropertyPlaceholderConfigurer && beanName.equals("placeholderProperties")) {
            ((PropertyPlaceholderConfigurer) bean).setIgnoreUnresolvablePlaceholders(true);
        }

        return bean;
    }
}