spring - Access all Environment properties as a Map or Properties object

Question

I am using annotations to configure my spring environment like this:

@Configuration
...
@PropertySource("classpath:/config/default.properties")
...
public class GeneralApplicationConfiguration implements WebApplicationInitializer 
{
    @Autowired
    Environment env;
}

This leads to my properties from default.properties being part of the Environment. I want to use the @PropertySource mechanism here, because it already provides the possibility to overload properties through several fallback layers and different dynamic locations, based on the environment settings (e.g. config_dir location). I just stripped the fallback to make the example easier.

However, my problem now is that I want to configure for example my datasource properties in default.properties. You can pass the settings to the datasource without knowing in detail what settings the datasource expects using

Properties p = ...
datasource.setProperties(p);

However, the problem is, the Environment object is neither a Properties object nor a Map nor anything comparable. From my point of view it is simply not possible to access all values of the environment, because there is no keySet or iterator method or anything comparable.

Properties p <=== Environment env?

Am I missing something? Is it possible to access all entries of the Environment object somehow? If yes, I could map the entries to a Map or Properties object, I could even filter or map them by prefix - create subsets as a standard java Map ... This is what I would like to do. Any suggestions?

Answer 1

You need something like this, maybe it can be improved. This is a first attempt:

...
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.AbstractEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
...

@Configuration
...
@org.springframework.context.annotation.PropertySource("classpath:/config/default.properties")
...
public class GeneralApplicationConfiguration implements WebApplicationInitializer 
{
    @Autowired
    Environment env;

    public void someMethod() {
        ...
        Map<String, Object> map = new HashMap();
        for(Iterator it = ((AbstractEnvironment) env).getPropertySources().iterator(); it.hasNext(); ) {
            PropertySource propertySource = (PropertySource) it.next();
            if (propertySource instanceof MapPropertySource) {
                map.putAll(((MapPropertySource) propertySource).getSource());
            }
        }
        ...
    }
...

Basically, everything from the Environment that's a MapPropertySource (and there are quite a lot of implementations) can be accessed as a Map of properties.