Manage java property files using Apache Common Configuration API

Recently I did some research on how to manage the java property file in a better way. I found the Apache Common Configuration API  is actually really good.

I found the following 3 features are really powerful.

1. Variable interpolation
  Like using a variable in Ant, you can use variable in a property file, and Apache Common Configuration API proivide API to expand them on the fly.
code sample

	/* variable.properties
	user.name=steve
	user.password=pass
	credential.string=${user.name}:${user.password}
	*/
	public void test_variable_interpolation() {
	try {
	PropertiesConfiguration config = new PropertiesConfiguration(
	"variable.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();
	}
	}

view raw variable_interpolation hosted with ❤ by GitHub

2. Include other property files in a property file
   check this link for details.
property example

	#config.properties
	user=amanda
	include=${user}.properties
	connection.string=${user.name}:${user.password}
	#amanda.properties
	user.name=Amanda Zhu
	user.password=8888

view raw config.properties hosted with ❤ by GitHub

Code example:

	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();
	}
	}

view raw include_single_file hosted with ❤ by GitHub

3. combine multiple property file into one property object
   details are in here.
   Property example

	#user.properties
	user.name=steve
	user.password=nobody
	#app.properties
	connection.string=${user.name}:${user.password}

view raw multi_Props hosted with ❤ by GitHub

   Code example:

	public void test_load_2_files() {
	CompositeConfiguration config = new CompositeConfiguration();
	try {
	config.addConfiguration(new PropertiesConfiguration(
	"user.properties"));
	config.addConfiguration(new PropertiesConfiguration(
	"app.properties"));
	Configuration extConfig = 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) {
	e.printStackTrace();
	}
	}

view raw load_2_files hosted with ❤ by GitHub

I believe above the 3 features will greatly simply the java property file management.