Load configuration files dynamically using Spring - spring

Question

We already have a setup in which we are loading files like :
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>file:${AN_ENV_CONFIGURED_DIR}/project.properties</value>
</list>
</property>
The config files are there in server in a separate location. I want to load the configuration files dynamically if there is a change in it. Now since I already have this setup is there a simple way to reload config files from Spring other than using TimerTask and if its the only way then still its not sufficing the need to loading the file immediately.

Answer 1

You can use ReloadableResourceBundleMessageSource, following is the code snippet.
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basenames">
<list>
<value>file:${AN_ENV_CONFIGURED_DIR}/project.properties</value>
</list>
</property>
<property name="cacheSeconds" value="1"/>
</bean>
For more info : http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/context/support/ReloadableResourceBundleMessageSource.html

Answer 2

Use the below bean to reload config.properties every 1 second.
#Component
public class PropertyLoader {
#Autowired
private StandardEnvironment environment;
#Scheduled(fixedRate=1000)
public void reload() throws IOException {
MutablePropertySources propertySources = environment.getPropertySources();
PropertySource<?> resourcePropertySource = propertySources.get("class path resource [config.properties]");
Properties properties = new Properties();
InputStream inputStream = getClass().getResourceAsStream("/config.properties");
properties.load(inputStream);
inputStream.close();
propertySources.replace("class path resource [config.properties]", new PropertiesPropertySource("class path resource [config.properties]", properties));
}
}
Your main config will look something like:
#EnableScheduling
#PropertySource("classpath:/config.properties")
public class HelloWorldConfig {
}
Then access the property any where:
#Autowired
private Environment environment;
environment.get("my.property");