1、maven库

<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.9.0</version>
</dependency>

2、设置算法

//HMAC
Algorithm algorithmHS = Algorithm.HMAC256("secret");

//RSA
RSAPublicKey publicKey = //Get the key instance
RSAPrivateKey privateKey = //Get the key instance
Algorithm algorithmRS = Algorithm.RSA256(publicKey, privateKey);

3、创建并签名token

try {
    Algorithm algorithm = Algorithm.HMAC256("secret");
    String token = JWT.create()
        .withIssuer("auth0")
        .withExpiresAt(date)
        .withClaim("username", username)
        .sign(algorithm);
} catch (JWTCreationException exception){
    //Invalid Signing configuration / Couldn't convert Claims.
}

4、校验token

# 需要校验payload和signature
String token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXUyJ9.eyJpc3MiOiJhdXRoMCJ9.AbIJTDMFc7yUa5MhvcP03nJPyCPzZtQcGEp-zWfOkEE";
try {
    Algorithm algorithm = Algorithm.HMAC256("secret");
    JWTVerifier verifier = JWT.require(algorithm)
        .withIssuer("auth0")
        .build(); //Reusable verifier instance
    DecodedJWT jwt = verifier.verify(token);
} catch (JWTVerificationException exception){
    //Invalid signature/claims
}

5、解码获得信息

String token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXUyJ9.eyJpc3MiOiJhdXRoMCJ9.AbIJTDMFc7yUa5MhvcP03nJPyCPzZtQcGEp-zWfOkEE";
try {
    DecodedJWT jwt = JWT.decode(token);
} catch (JWTDecodeException exception){
    //Invalid token
}
Claim claim = jwt.getClaim("isAdmin");
String string = claim.asString();