JWT实现及工具类编写（使用jwt）

JWT 实现

1. 导入依赖

   <dependency>
       <groupId>com.auth0groupId>
       <artifactId>java-jwtartifactId>
       <version>3.18.2version>
   dependency>
   

2. 创建令牌

   public static String secretKey = "!QAZ@123#asd.$";
   @Test
   public void JWTCreatTest(){
       Map<String, Object> map = new HashMap<>();
       Calendar instance = Calendar.getInstance();
       //7天后过期
       instance.add(Calendar.DATE,7);
       String token = JWT.create().withHeader(map)
           .withClaim("userId",1)
           .withClaim("userName","WuYufan")
           .withExpiresAt(instance.getTime())
           .sign(Algorithm.HMAC256(secretKey));
       System.out.println(token);
   }
   

   生成的令牌：

   eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyTmFtZSI6Ild1WXVmYW4iLCJleHAiOjE2MzI3MTk3MTYsInVzZXJJZCI6MX0.uFkoaDEIqOtHj6P8IFosE809fu4V5PgG2ezSczc9mlY
   

   withHeader：添加标头(Header)

   withClaim：添加有效载荷(Payload)

   withExpiresAt：设置过期时间

   sign：添加签名(Signature) ； Algorithm.HMAC256 为加密算法

3. 根据令牌和签名解析数据

   @Test
   public void getInfoByToken(){
       //创建验证对象
       JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(secretKey)).build();
       //验证对象根据 token 获取DecodedJWT对象，该对象可以读取token中的数据
       DecodedJWT verify = jwtVerifier.verify("eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyTmFtZSI6Ild1WXVmYW4iLCJleHAiOjE2MzI3MTk3MTYsInVzZXJJZCI6MX0.uFkoaDEIqOtHj6P8IFosE809fu4V5PgG2ezSczc9mlY");
   
       Integer userId = verify.getClaim("userId").asInt();
       String userName = verify.getClaim("userName").asString();
       //过期时间
       Date expirationTime = verify.getExpiresAt();
       System.out.println("userId = " + userId);
       System.out.println("userName = " + userName);
       System.out.println("expirationTime = " + expirationTime);
   }
   

   运行结果：

   userId = 1
   userName = WuYufan
   expirationTime = Mon Sep 27 13:15:16 CST 2021
   

常见异常：

• SignatureverificationException : 签名不一致异常
• TokenExpiredException: 令牌过期异常
• AlgorithmNismatchException: 算法不匹配异常
• InvalidClaimException : 失效的payload异常

编写 JWT 工具类

package cn.edu.hziee.boot.utils;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTCreator;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.DecodedJWT;

import java.util.Calendar;
import java.util.Map;

public class JWTUtils {

	// 密钥
    private static final String SECRETKEY = "!QAzxZ@12^3#asd..0..";

    /**
     * 获取令牌
     * @param map 填入的用户信息
     * @return token 生成的令牌
     */
    public static String getToken(Map<String, Object> map){
        Calendar instance = Calendar.getInstance();
        instance.add(Calendar.DATE,7);

        //创建 JWT builder
        JWTCreator.Builder builder = JWT.create();

        map.forEach((k,v)->{
        	builder.withClaim(k,v);
        });
        
        String token = builder.withExpiresAt(instance.getTime())
                .sign(Algorithm.HMAC256(SECRETKEY));
        return token;
    }

    /**
     * 验证 token 的合法性，并返回其信息
     * @param token 需要验证的 token
     * @return 返回 token 信息（DecodedJWT 对象）
     */
    public static DecodedJWT verify(String token){
        return JWT.require(Algorithm.HMAC256(SECRETKEY)).build().verify(token);
    }
}