解决方法
使用
ExternalContext#getResource()或
ExternalContext#getResourceAsStream(),其中传递webcontent相对路径.
例如.：
ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
Properties properties = new Properties();
// ...
properties.load(externalContext.getResourceAsStream("/WEB-INF/file.properties"));
这将委托给ServletContext#getResource()/ getResourceAsStream().
也可以看看：
> Where to place and how to read configuration resource files in servlet based application?
