转载java实现md5加密解密

  import java.security.MessageDigest;

    /**
     * MD5技术加密解密
     */
    public class MD5Tools {

        public static String bytesToHexString(byte[] src) {
            StringBuilder stringBuilder = new StringBuilder("");
            if (src == null || src.length <= 0) {
                return null;
            }
            for (int i = 0; i < src.length; i++) {
                int v = src[i] & 0xFF;
                String hv = Integer.toHexString(v);
                if (hv.length() < 2) {
                    stringBuilder.append(0);
                }
                stringBuilder.append(hv);
            }
            return stringBuilder.toString();
        }

        /**
         * 解析
         * @param hexString
         * @return
         */
        public static byte[] hexStringToBytes(String hexString) {
            if (hexString == null || hexString.equals("")) {
                return null;
            }
            hexString = hexString.toUpperCase();
            int length = hexString.length() / 2;
            char[] hexChars = hexString.toCharArray();
            byte[] d = new byte[length];
            for (int i = 0; i < length; i++) {
                int pos = i * 2;
                d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
            }
            return d;
        }

        /**
         * 将指定byte数组以16进制的形式打印到控制台
         * @param b
         */
        public static void printHexString(byte[] b) {
            for (int i = 0; i < b.length; i++) {
                String hex = Integer.toHexString(b[i] & 0xFF);
                if (hex.length() == 1) {
                    hex = '0' + hex;
                }
                System.out.print(hex.toUpperCase());
            }

        }

        /**
         * Convert char to byte
         * @param c char
         * @return byte
         */
        private static byte charToByte(char c) {
            return (byte) "0123456789abcdef".indexOf(c);
        }

        /**
         * 加密
         * @param str
         * @return
         */
        public static String encode(String str) {
            String strDigest = "";
            try {
                // 此 MessageDigest 类为应用程序提供信息摘要算法的功能，必须用try,catch捕获
                MessageDigest md5 = MessageDigest.getInstance("MD5");

                byte[] data;
                data = md5.digest(str.getBytes("utf-8"));// 转换为MD5码
                strDigest = bytesToHexString(data);
            } catch (Exception ex) {
                throw new RuntimeException(ex);
            }
            return strDigest;
        }

    }

转载自：

https://blog.csdn.net/wwz95/article/details/78524984