MD5加密之加密字符串

public static String encode(String str) {
        String encodeString = "";

        try {
            MessageDigest md = MessageDigest.getInstance("md5");
            // 用MD5加密后的字节数组
            byte[] digest = md.digest(str.getBytes());
            for (byte b : digest) {
                // 将前面的ffffff去掉
                int temp = b & 0x000000ff;
                // 得到16进制
                String s = Integer.toHexString(temp);
                // 使每一位上都有两个数
                if (s.length() == 1) {
                    s = "0" + s;
                }

                encodeString += s;
            }
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return encodeString;
    }