参考

Java与.Net实现实现

// java HMacsha256private static final  String MAC_INSTANCE_NAME = "HMacSHA256";public static String Hmacsha256(String secret, String message) throws NoSuchAlgorithmException, InvalidKeyException {    Mac hmac_sha256 = Mac.getInstance(MAC_INSTANCE_NAME);    SecretKeySpec key = new SecretKeySpec(secret.getBytes(), MAC_INSTANCE_NAME);    hmac_sha256.init(key);    byte[] buff = hmac_sha256.doFinal(message.getBytes());    return Base64.encodeBase64URLSafeString(buff);}// java jwt@Testpublic void testJWT() throws InvalidKeyException, NoSuchAlgorithmException {    String secret = "eerp";    String header = "{\"type\":\"JWT\",\"alg\":\"HS256\"}";    String claim = "{\"iss\":\"cnooc\", \"sub\":\"yrm\", \"username\":\"yrm\", \"admin\":true}";    String base64Header = Base64.encodeBase64URLSafeString(header.getBytes());    String base64Claim = Base64.encodeBase64URLSafeString(claim.getBytes());    String signature = ShaUtil.Hmacsha256(secret, base64Header + "." + base64Claim);    String jwt = base64Header + "." + base64Claim  + "." + signature;    System.out.println(jwt);}// c# Hmacsha256protected String HMacSha256Hash(String key, String message){    var keyBytes = Encoding.UTF8.GetBytes(key);    using (var hmacsha256 = new HMACSHA256(keyBytes))    {        var buffer = hmacsha256.ComputeHash(Encoding.UTF8.GetBytes(message));        var b64 = Base64UrlSafeString(buffer);        return b64;    }}protected String Base64UrlSafeString(Byte[] bytes){    var b64 = Convert.ToBase64String(bytes);    return b64.Replace("=", "").Replace("+", "-").Replace("/", "_");}// c# jwt[Test]public void testJWT(){    String secret = "eerp";    String header = "{\"type\":\"JWT\",\"alg\":\"HS256\"}";    String claim = "{\"iss\":\"cnooc\", \"sub\":\"yrm\", \"username\":\"yrm\", \"admin\":true}";    var encoding = Encoding.UTF8;    var base64Header = Base64UrlSafeString(encoding.GetBytes(header));    var base64Claim = Base64UrlSafeString(encoding.GetBytes(claim));    var signature = HMacSha256Hash(secret, base64Header + "." + base64Claim);    var jwt = base64Header + "." + base64Claim + "." + signature;    Console.WriteLine(jwt);}

结果:

eyJ0eXBlIjoiSldUIiwiYWxnIjoiSFMyNTYifQ.eyJpc3MiOiJjbm9vYyIsICJzdWIiOiJ5cm0iLCAidXNlcm5hbWUiOiJ5cm0iLCAiYWRtaW4iOnRydWV9.sAHcCnpnsPA0T9i-Ig9oZnVq3N0-kK_aCwlkzFOkrH8