使用Spring Boot时无法解析@PropertySource中的$ {…}

Question

I am using Spring's Java configuration to configure my application. Below is a snippet of the annotations. There is no problem with the application deployed to the Tomcat container. The ${CONFIG_PATH} resolves correctly as the CONFIG_PATH is defined in the system/environment properties.

@Configuration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.ANNOTATION, value = { Configuration.class }) })
@PropertySource(value = { "file:${CONFIG_PATH}/app.properties" })
@EnableAutoConfiguration
@EnableMongoRepositories
public class AppConfig { ... }

I recently started using Spring-Boot so that I can build a standalone executable jar with Tomcat embedded. However, now the @PropertySource(value = { "file:${CONFIG_PATH}/app.properties" }) does not work; it results in the following error.

Exception in thread "main" java.lang.IllegalStateException: Resource not found: file:${CONFIG_PATH}/app.properties

My temporary solution is to hardcode the path as follows.

//@PropertySource(value = { "file:${CONFIG_PATH}/app.properties" })
@PropertySource(value = { "file:/usr/local/etc/app.properties" })

I'm still relatively new to the Spring camp. So I'm sure that I'm missing something. I greatly appreciate any help on this problem.

Thanks in advance.

UPDATE 1 : I looked the at the default appplication.properties and found the 4 location given to be wanting. For reasons of clean deployment, properties file should be not located in the classpath. And having the properties file located relative to where the application is located makes it harder to manage the configuration if we have more than one application deployed.

Answer 1

From the Spring Boot README

If you don't like application.properties as the configuration file name you can switch to another by specifying spring.config.name environment property. You can also refer to an explicit location using the spring.config.location environment property.

I would probably just use this startup parameter (in a bootscript or something) to specify the configuration file.

I guess the reason the replacement doesn't work is due to the nature of spring boot. The application context is also used to bootstrap/configure the servlet container and as such the normal rules for @PropertySource probably doesn't apply. You could (or maybe should) register an issue for this.