Java中JWT的使用的详细教程

{
  "alg": "HS256",
  "typ": "JWT"
}

iss：发行人
exp：到期时间
sub：主题
aud：用户
nbf：在此之前不可用
iat：发布时间
jti：JWT ID用于标识该JWT

{
  "id": "123",
  "name": "cheng"
}

<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.10.3</version>
</dependency>

/**
     * 生成JWT token
     */
    @Test
    void generateToken(){
        //预设一个token过期时间
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.HOUR,1);//过期时间为1小时
        String token = JWT.create()
                .withHeader(new HashMap<>())//Header
                .withClaim("userId", 123)//PayLoad
                .withClaim("userName", "程")
                .withClaim("userId1", "456")
                .withExpiresAt(calendar.getTime())//过期时间
                .sign(Algorithm.HMAC256("12345"));//签名用的密钥secret
        System.out.println(token);
    }

    /**
     * 解析jwt字符串
     */
    @Test
    void resolveToken(){
        String token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VySWRJbnQiOjEyMywidXNlcklkU3RyaW5nIjoiNDU2IiwidXNlck5hbWUiOiLnqIsiLCJleHAiOjE2NzU5MTQzMDZ9.MNC-YCxt8C0t9SNbj3_XMRknkK3-PKBP5xX6_JLB8y8";
        //创建解析对象，使用的算法和secret要和创建token时保持一致
        JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256("12345")).build();
        DecodedJWT decodedJWT = jwtVerifier.verify(token);
        System.out.println(decodedJWT.getPayload());//base64编码的payLoad
        Claim userIdInt = decodedJWT.getClaim("userIdInt");
        Claim userIdString = decodedJWT.getClaim("userIdString");
        Claim userName = decodedJWT.getClaim("userName");
        System.out.println("userIdInt:"+userIdInt.asInt());
        System.out.println("userIdString:"+userIdString.asString());
        System.out.println("userName:"+userName.asString());
        System.out.println("过期时间:"+new LocalDateTime(decodedJWT.getExpiresAt()));
    }

private static final String RSA_PRIVATE_KEY = "...";
private static final String RSA_PUBLIC_KEY = "...";

    /**
     * 生成token
     * @param payload token携带的信息
     * @return token字符串
     */
public static String getTokenRsa(Map<String,String> payload){
    // 指定token过期时间为7天
    Calendar calendar = Calendar.getInstance();
    calendar.add(Calendar.DATE, 7);

    JWTCreator.Builder builder = JWT.create();
    // 构建payload
    payload.forEach((k,v) -> builder.withClaim(k,v));

    // 利用hutool创建RSA
    RSA rsa = new RSA(RSA_PRIVATE_KEY, null);
    // 获取私钥
    RSAPrivateKey privateKey = (RSAPrivateKey) rsa.getPrivateKey();
    // 签名时传入私钥
    String token = builder.withExpiresAt(calendar.getTime()).sign(Algorithm.RSA256(null, privateKey));
    return token;
}

    /**
     * 解析token
     * @param token token字符串
     * @return 解析后的token
     */
public static DecodedJWT decodeRsa(String token){
    // 利用hutool创建RSA
    RSA rsa = new RSA(null, RSA_PUBLIC_KEY);
    // 获取RSA公钥
    RSAPublicKey publicKey = (RSAPublicKey) rsa.getPublicKey();
    // 验签时传入公钥
    JWTVerifier jwtVerifier = JWT.require(Algorithm.RSA256(publicKey, null)).build();
    DecodedJWT decodedJWT = jwtVerifier.verify(token);
    return decodedJWT;
}