如何判断一个大整数（10000-9999999999）的量级并用拼音表示？

import java.util.Scanner;

public class IntegerMagnitude {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        String a = "" + n;
        String magnitude;

        switch (a.length()) {
            case 5:
                magnitude = "wan";
                break;
            case 6:
                magnitude = "shi wan";
                break;
            case 7:
                magnitude = "bai wan";
                break;
            case 8:
                magnitude = "qian wan";
                break;
            case 9:
                magnitude = "yi";
                break;
            case 10:
                magnitude = "shi yi";
                break;
            default:
                magnitude = "超出范围";
                break;
        }
        System.out.println(magnitude);
        scanner.close();
    }
}