Specifying relative path in application.properties in Spring

Question

Is there a way we can lookup file resources using relative path in application.properties file in Spring boot application as specified below

spring.datasource.url=jdbc:hsqldb:file:${project.basedir}/db/init

Answer 1

@membersound answer is just breaking up the hardcoded path in 2 parts, not dynamically resolving the property. I can tell you how to achieve what you're looking for, but you need to understand is that there is NO project.basedir when you're running the application as a jar or war. Outside the local workspace, the source code structure doesn't exist.

If you still want to do this for testing, that's feasible and what you need is to manipulate the PropertySources. Your simplest option is as follows:

Define an ApplicationContextInitializer, and set the property there. Something like the following:

    public class MyApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    @Override
    public void initialize(ConfigurableApplicationContext appCtx) {
        try {
            // should be /<path-to-projectBasedir>/build/classes/main/
            File pwd = new File(getClass().getResource("/").toURI());
            String projectDir = pwd.getParentFile().getParentFile().getParent();
            String conf = new File(projectDir, "db/init").getAbsolutePath();
            Map<String, Object> props = new HashMap<>();
            props.put("spring.datasource.url", conf);
            MapPropertySource mapPropertySource = new MapPropertySource("db-props", props);
            appCtx.getEnvironment().getPropertySources().addFirst(mapPropertySource);
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }
    }}

Looks like you're using Boot, so you can just declare context.initializer.classes=com.example.MyApplicationContextInitializer in your application.properties and Boot will run this class at startup.

Words of caution again:

1. This will not work outside the local workspace as it depends on the source code structure.

2. I've assumed a Gradle project structure here /build/classes/main. If necessary, adjust according to your build tool.

3. If MyApplicationContextInitializer is in the src/test/java, pwd will be <projectBasedir>/build/classes/test/, not <projectBasedir>/build/classes/main/.