@PropertySource 中的类路径通配符

Question

I am using Spring Java config to create my bean. But this bean is common to 2 applications. Both have one property file abc.properties but with different classpath locations. When i put explicit classpath like

@PropertySource("classpath:/app1/abc.properties")

then it works but when i try to use wildcard like

@PropertySource("classpath:/**/abc.properties")

then it doesn't work. I try many combinations of wildcard but it still not working. Is wildcard works in @ProeprtySource Is there any other way to read to property in classed marked with @Configurations .

Answer 1

@PropertySource API: Resource location wildcards (eg **/*.properties) are not permitted; each location must evaluate to exactly one .properties resource. Resource location wildcards (eg **/*.properties) are not permitted; each location must evaluate to exactly one .properties resource.

workaround: try

@Configuration
public class Test {

    @Bean
    public PropertyPlaceholderConfigurer getPropertyPlaceholderConfigurer()
            throws IOException {
        PropertyPlaceholderConfigurer ppc = new PropertyPlaceholderConfigurer();
        ppc.setLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/**/abc.properties"));
        return ppc;
    }

Answer 2

Addidtionally to dmay workaround:

Since Spring 3.1 PropertySourcesPlaceholderConfigurer should be used preferentially over PropertyPlaceholderConfigurer and the bean should be static.

@Configuration
public class PropertiesConfig {

  @Bean
  public static PropertySourcesPlaceholderConfigurer placeHolderConfigurer() {
    PropertySourcesPlaceholderConfigurer propertyConfigurer = new PropertySourcesPlaceholderConfigurer();
    propertyConfigurer.setLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/**/abc.properties"));
    return propertyConfigurer;
  }

}

Answer 3

If you're using YAML properties, this can be achieved using a custom PropertySourceFactory :

public class YamlPropertySourceFactory implements PropertySourceFactory {

    private static final Logger logger = LoggerFactory.getLogger(YamlPropertySourceFactory.class);

    @Override
    @NonNull
    public PropertySource<?> createPropertySource(
            @Nullable String name,
            @NonNull EncodedResource encodedResource
    ) {
        YamlPropertiesFactoryBean factory = new YamlPropertiesFactoryBean();
        String path = ((ClassPathResource) encodedResource.getResource()).getPath();
        String filename = encodedResource.getResource().getFilename();
        Properties properties;
        try {
            factory.setResources(
                    new PathMatchingResourcePatternResolver().getResources(path)
            );
            properties = Optional.ofNullable(factory.getObject()).orElseGet(Properties::new);
            return new PropertiesPropertySource(filename, properties);
        } catch (Exception e) {
            logger.error("Properties not configured correctly for {}", path, e);
            return new PropertiesPropertySource(filename, new Properties());
        }
    }
}

Usage:

@PropertySource(value = "classpath:**/props.yaml", factory = YamlPropertySourceFactory.class)
@SpringBootApplication
public class MyApplication {
    // ...
}