定义一个phone类把其中的一些变量定义为private，通过Phonef方法获取phoneNumber，再通过get和set方法获取phoneNumber的区号和号码。通过重写Tostring方法分别输入电话号码和输出电话号码，同时用到啦String.indexOf( )和 String.substring( )获取区号和号码，最好在主函数中输出区号和号码。-Define a phone class to which some variables defined for private, access to phoneNumber through the Phonef method, and then the area code and number for phoneNumber by get and set methods. Enter phone number and telephone number output by overriding the Tostring method, and use String.indexOf () and String.substring () to obtain the area code and number, the best output the area code and number in the main function.