ResourceBundle

  //resourcebundle 为包名，Common为properties文件名， "." 可以替换成"/"
    Locale locale1 = new Locale("zh", "CN");
    Locale locale2 = new Locale("en", "US");
    ResourceBundle bundle = ResourceBundle.getBundle("resourcebundle.Common", locale2);
    System.out.println("bundle: " + bundle);
    System.out.println(bundle.getString("userName"));