External properties file in spring

Question

I have a java,spring and not spring boot command line program with maven , which when i build a jar with all dependencies using maven-assembly-plugin , it includes application.properties, what i need to know is how to read the external application.properties and not the jar one.

I am reading the property file as:

@PropertySource(value = { "classpath:application.properties" })

If I print the classpath, the classpath does only include the jar and not the current directory.

Answer 1

Here is what you can do:

@PropertySources({
    @PropertySource("classpath:application.properties"),
    @PropertySource(value = "file:/etc/config/my-custom-config.properties", ignoreResourceNotFound = true)
})

This ignoreResourceNotFound is available since spring 4.3 and is pretty self-explanatory.

You can also opt for "programmatic" approach. In pure spring (not spring boot as you've mentioned in the question):

@Configuration
public class CommonConfig {
...
        @Bean
        public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
            PropertySourcesPlaceholderConfigurer ppc = new PropertySourcesPlaceholderConfigurer();
            ppc.setLocations(new FileSystemResource("/etc/config/my-custom-config.properties"),
                    new ClassPathResource("config/application.properties"),
            return ppc;
        }
...
}

FileSystemResource is for accessing resources available externally in the file system

ClassPathResource is for accessing resources in the classpath

Answer 2

We use dynamically generated configuration files that are injected with environment specific secrets. The combination to get everything aligned is as follows:

Code:

    myFunction(@Value("${custom.configuration.name}") final String customConfigurationName) {
        InputStream inputStream=new ClassPathResource(customconfigFileName).getInputStream()){}
        ...
    }

Template - Add a hard required path as this confirms the file is on disk and loaded:

- name: SPRING_CONFIG_LOCATION
  value: file:./config/schema-${ENV}.yml
  ...
- name: custom.configuration.name
  value: file:config/schema-${ENV}.yml