JAVA switc购买

public class Switch {
    public static void main(String[] args) {
        System.out.println("请输入你想要购买的商品序号");
        System.out.println("1：可乐 2：牛奶 3：苹果");
        Scanner s1 = new Scanner(System.in);
        int a = s1.nextInt();
        switch (a){
            case 1:
                System.out.println("已成功购买可乐");
            break;
            case 2:
                System.out.println("已成功购买牛奶");
            break;
            case 3:
                System.out.println("已成功购买苹果");
                break;
            default :
                System.out.println("你输入的序号不正确");
                break;
        }

    }
}