MD5算法

public static String md5(String source) {

    try {
        String str = source;
        MessageDigest md = MessageDigest.getInstance("MD5");// 利用哈希算法，MD5
        byte[] output = md.digest(str.getBytes());
        StringBuilder stringBuilder = new StringBuilder("");
        for (int i = 0; i < output.length; i++) {
            int v = output[i] & 0xFF;
            String hv = Integer.toHexString(v);
            if (hv.length() < 2) {
                stringBuilder.append(0);
            }
            stringBuilder.append(hv);
        }
        return stringBuilder.toString();
    } catch (Exception ex) {
        ex.printStackTrace();
        return null;
    }
}