Usage of hexadecimal conversion BigInteger

import java.math.BigInteger;    //调包
import java.util.Scanner;
//BigInteger(需要转换的数,这个数是几进制).toString(需要转换成的进制)
public class New_Base_Conversion {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入需要转换的进制：（输入数字即可）");
        int base_1 = input.nextInt();
        System.out.println("请输入需要把" + base_1 + "进制转换成什么进制");
        int base_02 = input.nextInt();
        System.out.println("请输入需要转换的数");
        String str = input.next();
        System.out.println(base_1 + "进制数" + str + "转换成" + base_02 + "进制数为：" + new BigInteger(str,base_1).toString(base_02));
    }
}