java中如何从键盘输入单个字符并用在while表达式中

public static void main(String[] args) {
    char n = 0;
    String y;
    Scanner input = new Scanner(System.in);
    System.out.println("请输入你的会员卡号:");
    String vipNumber = input.next();
    System.out.println("请输入你的会员积分:");
    double vipScore = input.nextDouble();

    Object st = null;
    do {

        if (vipScore >= 5000 && vipScore < 15000) {
            Gift gift = new Gift();
            gift.name = "vivo手机一部";
            gift.price = 5300;
            System.out.println("恭喜你！获得:" + gift.toString());
        } else if (vipScore >= 15000) {
            Gift gift = new Gift();
            gift.name = "笔记本电脑";
            gift.price = 12000;
            System.out.println("恭喜你!获得" + gift.toString());
        } else {
            System.out.println("对不起，你的积分不足");
        }

    } while (st.equals(y));
    System.out.println("请问是否继续,继续请输入y,结束请输入n");
    String st = input.next();

}

String vipNumber = input.next();
vipNumber.ChartAt(0)可以获得字符

你这继续输入也应该放在while循环内。

public static void main(String[] args) {
    char n = 0;
    String y;
    Scanner input = new Scanner(System.in);
    System.out.println("请输入你的会员卡号:");
    String vipNumber = input.next();
    System.out.println("请输入你的会员积分:");
    double vipScore = input.nextDouble();
 
    String st = null;
    do {
        if (vipScore >= 5000 && vipScore < 15000) {
            Gift gift = new Gift();
            gift.name = "vivo手机一部";
            gift.price = 5300;
            System.out.println("恭喜你！获得:" + gift.toString());
        } else if (vipScore >= 15000) {
            Gift gift = new Gift();
            gift.name = "笔记本电脑";
            gift.price = 12000;
            System.out.println("恭喜你!获得" + gift.toString());
        } else {
            System.out.println("对不起，你的积分不足");
        }
 System.out.println("请问是否继续,继续请输入y,结束请输入n");
    st = input.next();
    } while (st.equals(y));
   
}