commons-configuration的使用

各独立相关的配置放在一个单独配置文件中,整个应用由一个统一的配置装配文件global-config.xml,然后统一个Configuration类实的例来获取各种配置参数 the ConfigurationFactory class:

ConfigurationFactory factory = new ConfigurationFactory("config.xml");
Configuration config = factory.getConfiguration();

The config.xml file used in the example above is a configuration descriptor,
it specifies the Configuration objects to load. 

Here is an example of descriptor:     

<?xml version="1.0" encoding="ISO-8859-1" ?>

<configuration>
<system/>
<properties fileName="application.properties"/>
</configuration>

What this says is that we are loading up all system properties,

as well as the propertiesfile application.properties.

The order of precedence is first to last.So in the above example,

if a property is not found in the system properties, it'll be searched in the properties file. This allows you to set up default values in a properties file, and override them with the system properties.

config.xml中格模块文件的配置顺序很重要,在前一配置中已找到配置参数值就不会再在后一文件中查找了

reference