java使用JWT的方法

{

   "alg" : "HS256" ,    // 指定签名算法

   "typ" : "JWT"        // 指定token令牌类型

}

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

Header.Payload.Signature

<!-- jwt -->

<dependency>

     <groupId>com.auth0</groupId>

     <artifactId>java-jwt</artifactId>

     <version>3.10.3</version>

</dependency>

package com.cxstar.utils;

import com.auth0.jwt.JWT;

import com.auth0.jwt.JWTCreator;

import com.auth0.jwt.algorithms.Algorithm;

import com.auth0.jwt.interfaces.DecodedJWT;

import com.auth0.jwt.interfaces.JWTVerifier;

import java.util.Calendar;

import java.util.Map;

public class JwtUtil {

     // 签名密钥

     private static final String SECRET = "hello JWT *%$#$&" ;

     /**

      * 生成token

      * @param payload token携带的信息

      * @return token字符串

      */

     public static String generateToken(Map<String,String> payload){

         // 指定token过期时间

         Calendar calendar = Calendar.getInstance();

         calendar.add(Calendar.HOUR, 24 );  // 24小时

         JWTCreator.Builder builder = JWT.create();

         // 构建payload

         payload.forEach(builder::withClaim);

         // 指定过期时间和签名算法，并返回token

         String token = builder.withExpiresAt(calendar.getTime()).sign(Algorithm.HMAC256(SECRET));

         return token;

     }

     /**

      * 解析token

      * @param token token字符串

      * @return 解析后的token类

      */

     public static DecodedJWT decodeToken(String token){

         JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(SECRET)).build();

         DecodedJWT decodedJWT = jwtVerifier.verify(token);

         return decodedJWT;

     }

}

package com.cxstar;

import com.auth0.jwt.exceptions.JWTDecodeException;

import com.auth0.jwt.exceptions.TokenExpiredException;

import com.auth0.jwt.interfaces.DecodedJWT;

import com.cxstar.utils.JwtUtil;

import org.junit.jupiter.api.Test;

import org.springframework.boot.test.context.SpringBootTest;

import java.util.HashMap;

import java.util.Map;

@SpringBootTest

class JwtLoginApplicationTests {

     @Test

     void tokenTest() {

         // 根据用户信息生成令牌 --------------------------

         Map<String, String> payload = new HashMap<>();

         payload.put( "userId" , "233" );

         payload.put( "userName" , "ps" );

         String token = JwtUtil.generateToken(payload);

         System.out.println( "token: " + token);

         // --------------------------------------------

         // 解析令牌并获取用户信息 ------------------------------------------------

         try {

             DecodedJWT decodedJWT = JwtUtil.decodeToken(token);

             String userId = decodedJWT.getClaim( "userId" ).asString();

             String userName = decodedJWT.getClaim( "userName" ).asString();

             String exp = decodedJWT.getExpiresAt().toString();

             System.out.println( "userId: " + userId);      // 取出自定义属性【用户id】

             System.out.println( "userName: " + userName);  // 取出自定义属性【用户名】

             System.out.println( "exp: " + exp);            // 取出默认属性【过期时间】

         } catch (JWTDecodeException e) {

             System.out.println( "令牌错误" );

         } catch (TokenExpiredException e) {

             System.out.println( "令牌过期" );

         }

         // -------------------------------------------------------------------

     }

}