java十进制转三十六进制

import java.util.HashMap;

public class Ten2Thirty {

    private static final String X36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    private static final String[] X36_ARRAY = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z".split(",");

    public static String tenTo36(int num) {
        StringBuffer sBuffer = new StringBuffer();

        if(num == 0) {
            sBuffer.append("0");
        }
        while(num > 0) {
            sBuffer.append(X36_ARRAY[num % 36]);
            num = num / 36;
        }

        return sBuffer.reverse().toString();
    }

    public static int thirtysixToTen(String string) {

        HashMap<Character, Integer> map = new HashMap<Character, Integer>();
        for (int i = 0; i < X36.length(); i++) {
            map.put(X36.charAt(i), i);
        }

        int size = string.length();
        int num = 0;
        for(int i = 0; i<size; i++) {
            String char2str = String.valueOf(string.charAt(i)).toUpperCase();
            num = (int) (map.get(char2str.charAt(0)) * Math.pow(36, size - i - 1) + num);
        }

        return num;
    }

    public static void main(String[] args) {
        System.out.println(tenTo36(100));
        System.out.println(thirtysixToTen("2S"));
        System.out.println(thirtysixToTen("2s"));
    }
}