Jwt Token

Header标头，Payload负载，Signature签名

public class jwtUtils { 
            private  static String key = "ASDFse@#w";  // 密钥     private static long validTime = 1000*60*1;  // 有效时间 1 分钟      /** * 创建 token * @param username * @return */     public static String createToken(String username){ 
                String token = Jwts.builder() // header                 .setHeaderParam("typ","jwtUtils")                 .setHeaderParam("alg","HS256") // payload                 .claim("username",username)                 .setSubject("大数据库作业")                 .setExpiration(new Date(System.currentTimeMillis()   validTime))                 .setId(UUID.randomUUID().toString()) // signature                 .signWith(SignatureAlgorithm.HS256,key)                 .compact();
        return token;
    }

    /** * 解析 token 判断是否正确 * @param token * @return */
    public static boolean VerifyToken (String token){ 
       
        JwtParser parser = Jwts.parser();
        Jws<Claims> claimsJws = parser.setSigningKey(key).parseClaimsJws(token);
        Claims cl = claimsJws.getBody();

        System.out.println(cl.get("username"));
        System.out.println(cl.getId());
        System.out.println(cl.getSubject());
        System.out.println(cl.getExpiration());

        System.out.println("//");
        String[] split = token.split("\\.");
        System.out.println(Base64Codec.BASE64.decodeToString(split[0]));    // header部分
        System.out.println(Base64Codec.BASE64.decodeToString(split[1]));    // payload 部分
        System.out.println(Base64Codec.BASE64.decodeToString(split[2]));    // signature 部分
        System.out.println("//");
        SimpleDateFormat simple = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println("当前时间" + simple.format(new Date()));
        System.out.println("过期时间" + simple.format(cl.getExpiration()));
        return true;
    }

    public static void main(String[] args) { 
       
        String token = createToken("haung和");
        System.out.println(token);
        VerifyToken(token);
    }
}

打印信息

# token
eyJ0eXAiOiJqd3RVdGlscyIsImFsZyI6IkhTMjU2In0
.eyJ1c2VybmFtZSI6ImhhdW5n5ZKMIiwic3ViIjoi5pWw5o2u5bqT5aSn5L2c5LiaIiwiZXhwIjoxNjU0NTA2MjYzLCJqdGkiOiI4Mzc0ZGZiNC1jNzQ2LTRjMmItYmYyOS1kZGEyZTRjMzIxNmMifQ
.cRGfKmMRqSyUD_16-RxZEApVJbY3AphcaKdCyEUQYz8
# username
haung和	
# jti 
8374dfb4-c746-4c2b-bf29-dda2e4c3216c
# subject 
数据库大作业
# expiration time 
Mon Jun 06 17:04:23 CST 2022				
//
# header 部分
{ 
       "typ":"jwtUtils","alg":"HS256 # payload 部分 {"username":"haung和","sub":"数据库大作业","exp":1654506263,"jti":"8374dfb4-c746-4c2b-bf29-dda2e4c3216c"
# signature 部分
q�*c�,�^�ő �R[cp)�Ɗt,�Q3
//
当前时间2022-06-06 17:03:24
过期时间2022-06-06 17:04:23

如果token过期的话，在VerifyToken 方法中，执行到

Jws<Claims> claimsJws = parser.setSigningKey(key).parseClaimsJws(token);

这一行的时候，就会报 ExpiredJwtException异常

Exception in thread "main" io.jsonwebtoken.ExpiredJwtException: 
JWT expired at 2022-06-06T17:04:23Z. Current time: 2022-06-06T17:07:16Z, 
a difference of 173801 milliseconds.  Allowed clock skew: 0 milliseconds.

token格式如果不对，则会报错

Exception in thread "main" io.jsonwebtoken.MalformedJwtException: 
JWT strings must contain exactly 2 period characters.

密钥不对，则报错

Exception in thread "main" io.jsonwebtoken.SignatureException:
 JWT signature does not match locally computed signature.

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