public void test_include_singl_file() {
		try {
			PropertiesConfiguration config = new PropertiesConfiguration(
					"config.properties");
			PropertiesConfiguration extConfig = (PropertiesConfiguration) config
					.interpolatedConfiguration();

			Iterator<String> iter = extConfig.getKeys();
			while (iter.hasNext()) {
				String key = iter.next();
				Object value = extConfig.getProperty(key);
				System.out.println("key=" + key + ",value=" + value);
			}

		} catch (ConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}