Detailed explanation of using JWT to create parsing tokens and RSA asymmetric encryption

<dependency>
  <groupId>.mingyang66</groupId>
  <artifactId>oceansky-jwt</artifactId>
  <version>4.3.2</version>
</dependency>

public class RsaPemCreatorFactory {
    /**
      * Public key file name
      */
    private static final String PUBLIC_KEY_FILE = "";
    /**
      * Private key file name
      */
    private static final String PRIVATE_KEY_FILE = "";
    private static final String publicKeyPrefix = "PUBLIC KEY";
    private static final String privateKeyPrefix = "PRIVATE KEY";
    /**
      * algorithm
      */
    public static final String ALGORITHM = "RSA";
    public static void create(String directory) throws NoSuchAlgorithmException, IOException {
        // algorithm specifies that the algorithm is RSA        KeyPairGenerator keyPairGenerator = (ALGORITHM);
        // Specify the key length to 2048        (1024);
        // Generate key        KeyPair keyPair = ();
        // If the folder does not exist, create it first        ((directory));
        try (FileWriter writer = new FileWriter(("", directory, PRIVATE_KEY_FILE));
             PemWriter pemWriter = new PemWriter(writer);
             FileWriter pubFileWriter = new FileWriter(("", directory, PUBLIC_KEY_FILE));
             PemWriter pubPemWriter = new PemWriter(pubFileWriter)) {
            (new PemObject(privateKeyPrefix, ().getEncoded()));
            (new PemObject(publicKeyPrefix, ().getEncoded()));
        } catch (IOException e) {
            ();
        }
    }
}

public class RsaAlgorithmFactory {
    public static final String N = "\n";
    public static final String R = "\r";
    public static final String ALGORITHM = "RSA";

    /**
      * Get the public key object
      *
      * @param publicKey public key string
      * @return Public key object
      * @throws InvalidKeySpecException
      * @throws NoSuchAlgorithmException
      */
    public static RSAPublicKey getPublicKey(String publicKey) throws InvalidKeySpecException, NoSuchAlgorithmException {
        if (publicKey == null || () == 0) {
            throw new IllegalArgumentException("Illegal Parameters");
        }
        byte[] keyBytes = ().decode((N, "").replace(R, "").getBytes(StandardCharsets.UTF_8));
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = (ALGORITHM);
        return (RSAPublicKey) (x509KeySpec);
    }

    /**
      * Get the private key object
      *
      * @param privateKey private key string
      * @return Private key object
      * @throws NoSuchAlgorithmException
      * @throws InvalidKeySpecException
      */
    public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        byte[] keyBytes = ().decode((N, "").replace(R, "").getBytes(StandardCharsets.UTF_8));
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = (ALGORITHM);
        return (RSAPrivateKey) (pkcs8KeySpec);
    }
}

public class JwtFactory {
    /**
      * Create a JWT Token string
      *
      * @param builder
      * @param algorithm
      * @return token string
      */
    public static String createJwtToken( builder, Algorithm algorithm) {
        // header:typ, alg algorithm        return (algorithm);
    }

    /**
      * Object after decoding of JWT string
      *
      * @param jwtToken
      * @param algorithm
      * @return parsed jwt token object
      */
    public static DecodedJWT verifyJwtToken(String jwtToken, Algorithm algorithm) {
        JWTVerifier jwtVerifier = (algorithm).build();
        return (jwtToken);
    }
}

    @Test
    public void test() throws InvalidKeySpecException, NoSuchAlgorithmException {
        RSAPublicKey publicKey = (publicKey1);

        //(new BouncyCastleProvider());
        RSAPrivateKey privateKey = (privateKey1);
        (());
        Map<String, Object> headers = new HashMap<>();
        ("ip", "123.12.123.25.12");
         builder = ()
                //JWT unique identifier jti                .withJWTId(().toString())
                .withHeader(headers)
                .withClaim("username", "Tian Runye")
                .withClaim("password", "dislike")
                //Published by iss                .withIssuer("Gu Yangmin")
                //Published time iat                .withIssuedAt((().atZone(()).toInstant()))
                //Audience|Recipient aud                .withAudience("Tian Haimin", "Sun Yuting")
                //Specify that JWT cannot accept processing before the specified time nbf                .withNotBefore((().plusMinutes(-1).atZone(()).toInstant()))
                //JWT's theme sub                .withSubject("Token")
                //JWT's key ID (actually not used), is used to specify the signature verification key kid com.                .withKeyId("sd")
                //JWT expiration time exp                .withExpiresAt(().plusMinutes(5).atZone(()).toInstant());
        String jwtToken = (builder, Algorithm.RSA256(publicKey, privateKey));
        (jwtToken);

        DecodedJWT jwt = (jwtToken, Algorithm.RSA256(publicKey, privateKey));
        (("username").asString(), "Tian Runye");
        (("password").asString(), "dislike");
        (("ip").asString(), "123.12.123.25.12");
        ((), "Gu Yangmin");
        (().get(0), "Tian Haimin");
        (().get(1), "Sun Yuting");
    }