Spring @Configuration file with PropertyPlaceholderConfigurer bean doesn't resolve @Value annotation

Question

I have following configuration file:

@Configuration
public class PropertyPlaceholderConfigurerConfig {

    @Value(\"${property:defaultValue}\")
    private          


        

Answer 1

If you run your application using VM option and then want to access that option in your application you have to do it slightly different:

@Value("#{systemProperties.property}")
private String property;

Your PropertyPlaceholderConfigurer is not aware of system properties, also note that you are accessing properties using $ - which refers to place holders and # refers to beans, where systemProperties is a bean.

Answer 2

For any other poor souls who couldn't get this to work in some Configuration classes when they work in others:

Look to see what other beans you have in that class and if any of them get instantiated early in the ApplicationContext. A ConversionService is an example of one. This would instantiate the Configuration class before what is required is registered, thereby making no property injection take place.

I fixed this by moving the ConversionService to another Configuration class that I Imported.

Answer 3

From Spring JavaDoc:

In order to resolve ${...} placeholders in definitions or @Value annotations using properties from a PropertySource, one must register a PropertySourcesPlaceholderConfigurer. This happens automatically when using in XML, but must be explicitly registered using a static @Bean method when using @Configuration classes. See the "Working with externalized values" section of @Configuration's javadoc and "a note on BeanFactoryPostProcessor-returning @Bean methods" of @Bean's javadoc for details and examples.

So, you are trying to use a placeholder in the code block required to enable placeholder processing.

As @M.Deinum mentioned, you should use a PropertySource (default or custom implementation).

Example below shows how to use properties in a PropertySource annotation as well as how to inject properties from the PropertySource in a field.

@Configuration
@PropertySource(
          value={"classpath:properties/${property:defaultValue}.properties"},
          ignoreResourceNotFound = true)
public class ConfigExample {

    @Value("${propertyNameFromFile:defaultValue}")
    String propertyToBeInjected;

    /**
     * Property placeholder configurer needed to process @Value annotations
     */
     @Bean
     public static PropertySourcesPlaceholderConfigurer propertyConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
     }
}