public void start() {

        System.out.println("************************************************************************");
        System.out.println("                         AddressBook                                    ");
        System.out.println("                  *A:add new User Address   ");
        System.out.println("                  *D:delete User            ");
        System.out.println("                  *S:search User by phoneNum");
        System.out.println("                  *L:list all User          ");
        System.out.println("                  *Q:Quit the program       ");
        System.out.println("************************************************************************");
        while (true) {

            System.out.print("please input the option(A/D/S/L/Q):");

            String readLine = getCommand();
            if (readLine.length() != 1) {
                System.out.print("input error,please input again");
                continue;
            }
            char c = readLine.toUpperCase().charAt(0);
            logger.info("user input the Option:" + c);
            switch (c) {
            case 'A':
                add();
                break;
            case 'D':
                delete();
                break;
            case 'S':
                search();
                break;
            case 'L':
                list(book.list());
                logger.info("list all users succesfully");
                break;
            case 'Q':
                if (quit())
                    return;
                break;
            }
        }
    }