Java JWT做登录认证

1.JWT的介绍

　　知乎有一篇文章介绍的很形象 认证方式的前世今生，以及 JWT 的使用

　　具体和Springboot的集成使用可参考另一篇博客：SpringBoot集成JWT实现token验证

2.使用demo　

package com.drz.proxy.internetProxy.util;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.StringUtils;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTCreationException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.auth0.jwt.interfaces.DecodedJWT;

/**
 * JWT token串结构: header.payload.signature 
 * signature=HMACSHA256(base64UrlEncode(header) + "." +base64UrlEncode(payload),Secret)
 * 
 * token保存在客户端，每次请求传到后端，服务端只保留密钥,不要把密钥放在header和payload中；
 * 
 * header中默认传递参数：
 * {"typ":"JWT","alg":"HS256"}
 * 
 * payload官方定义包含属性如下（非强制）：
 *     iss: jwt签发者
 *     sub: jwt所面向的用户
 *     aud: 接收jwt的一方
 *     exp: jwt的过期时间，这个过期时间必须要大于签发时间
 *     nbf: 定义在什么时间之前，该jwt都是不可用的.
 *     iat: jwt的签发时间
 *     jti: jwt的唯一身份标识，主要用来作为一次性token,从而回避重放攻击。
 * payload 自定义数据:存放我们想放在token中存放的key-value值
 */
public class JWTUtil {

    /**
     * 过期时间
     */
    private static final long EXPIRE_TIMEMILLS = 6000;

    /**
     * jwt 密钥
     */
    private static final String SECRET = "jwt_secret";

    public static String create() {
        try {
            Algorithm algorithm = Algorithm.HMAC256(SECRET);

            Map<String, Object> headerMap = new HashMap<String, Object>();
            headerMap.put("date", "2022-01-01 18:00");
            headerMap.put("where", "城东小树林");
            String token = JWT.create().withHeader(headerMap)//可自定义传递参数
                    //                    .withIssuer("auth0")//签发者
                    .withIssuedAt(new Date())//签发时间
                    .withSubject("subject").withAudience("100102134")
                    .withExpiresAt(new Date(System.currentTimeMillis() + EXPIRE_TIMEMILLS))
                    //payload中加入自定义数据
                    .withClaim("name", "小明").withClaim("introduce", "TTT").sign(algorithm);
            System.out.println("当前时间：" + new Date());
            System.out.println("jwt token:" + token);
            return token;
        } catch (JWTCreationException exception) {
            //Invalid Signing configuration / Couldn't convert Claims.
            throw exception;
        }
    }

    public static Boolean verify(String token) {
        try {
            Algorithm algorithm = Algorithm.HMAC256(SECRET);
            JWTVerifier verifier = JWT.require(algorithm).build(); //Reusable verifier instance
            DecodedJWT jwt = verifier.verify(token);

            String decodeHeader = StringUtils.newStringUtf8(Base64.decodeBase64(jwt.getHeader()));
            String decodePayload = StringUtils.newStringUtf8(Base64.decodeBase64(jwt.getPayload()));

            String signature = jwt.getSignature();
            String name = jwt.getClaim("name").asString();
            String introduce = jwt.getClaim("introduce").asString();

            System.out.println("header:" + jwt.getHeader());
            System.out.println("payload:" + jwt.getPayload());
            System.out.println("signature:" + signature);

            System.out.println("headerString:" + decodeHeader);
            System.out.println("payloadString:" + decodePayload);

            System.out.println("name:" + name);
            System.out.println("introduce:" + introduce);
            return true;
        } catch (JWTVerificationException exception) {
            System.out.println("当前时间：" + new Date());
            System.out.println("验证token失败：" + exception.getMessage());
            return false;
        }
    }

    public static void main(String[] args) {
        String token = create();
        //        try {
        //            Thread.sleep(3000l);
        //        } catch (InterruptedException e) {
        //            // TODO Auto-generated catch block
        //            e.printStackTrace();
        //        }
        Boolean result = verify(token);
        System.out.println(result);
    }
}

 输出结果：　

当前时间：Wed Jan 27 10:15:44 CST 2021

jwt token:eyJkYXRlIjoiMjAyMi0wMS0wMSAxODowMCIsIndoZXJlIjoi5Z-O5Lic5bCP5qCR5p6XIiwidHlwIjoiSldUIiwiYWxnIjoiSFMyNTYifQ.eyJzdWIiOiJzdWJqZWN0IiwiYXVkIjoiMTAwMTAyMTM0IiwiaW50cm9kdWNlIjoiVFRUIiwibmFtZSI6IuWwj-aYjiIsImV4cCI6MTYxMTcxMzc1MCwiaWF0IjoxNjExNzEzNzQ0fQ.LQIg264ZYVpq8SfPpv8gwJ3WnZtn_yk8fH8Cwg9Z69k

header:eyJkYXRlIjoiMjAyMi0wMS0wMSAxODowMCIsIndoZXJlIjoi5Z-O5Lic5bCP5qCR5p6XIiwidHlwIjoiSldUIiwiYWxnIjoiSFMyNTYifQ

payload:eyJzdWIiOiJzdWJqZWN0IiwiYXVkIjoiMTAwMTAyMTM0IiwiaW50cm9kdWNlIjoiVFRUIiwibmFtZSI6IuWwj-aYjiIsImV4cCI6MTYxMTcxMzc1MCwiaWF0IjoxNjExNzEzNzQ0fQ

signature:LQIg264ZYVpq8SfPpv8gwJ3WnZtn_yk8fH8Cwg9Z69k

headerString:{"date":"2022-01-01 18:00","where":"城东小树林","typ":"JWT","alg":"HS256"}

payloadString:{"sub":"subject","aud":"100102134","introduce":"TTT","name":"小明","exp":1611713750,"iat":1611713744}

name:小明

introduce:TTT

true