package cn.freemud.utils;

import java.security.MessageDigest;

/**
 *  MD5加密工具
 * @author liming.guo
 * @date 2018/05/11
 */
public class MD5Util {

    private static final String[] HEX_DIGITS = {"0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

    private static String byteArrayToHexString(byte[] b) {
        StringBuilder resultSb = new StringBuilder();
        for (byte aB : b) {
            resultSb.append(byteToHexString(aB));
        }
        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0) {
            n += 256;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return HEX_DIGITS[d1] + HEX_DIGITS[d2];
    }

    public static String MD5Encode(String origin, String charset) {
        String resultString = null;
        try {
            resultString = origin;
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charset == null || "".equals(charset)) {
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            } else {
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charset)));
            }
        } catch (Exception ignored) {
        }
        return resultString;
    }
}
