客户端用户登录生成token，然后返回给客户端后被存储，然后需要使用时客户端会发送到服务器进行验证。

package com.example.springblog;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtParser;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.io.Decoders;
import io.jsonwebtoken.io.Encoders;
import io.jsonwebtoken.security.Keys;
import org.junit.jupiter.api.Test;

import javax.crypto.SecretKey;
import java.security.Key;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class JWTUtisTest {
    //过期时间：1小时
    private final static  long EXPIRATION_DATE = 60*60*1000;
    //  secretString放的是一个已经生成的key
    private final static  String secretString ="y46vEE2Bv/LhfkRpqwKDxAGsTKT2p/IfOmplUfA89YE=";
    private final static Key key=Keys.hmacShaKeyFor(Decoders.BASE64.decode(secretString));
    //生成令牌
    @Test
    public  void genToken(){
//        Key key = Keys.hmacShaKeyFor(Decoders.BASE64.decode("y46vEE2Bv/LhfkRpqwKDxAGsTKT2p/IfOmplUfA89YE="));
        Map<String,Object> claim = new HashMap<>();
        claim.put("id",5);
        claim.put("name","zhnagsan");

        String token = Jwts.builder()
                .setClaims(claim)
                .setExpiration(new Date(System.currentTimeMillis()+EXPIRATION_DATE))
                .signWith(key)
                .compact();
        System.out.println(token);

    }
    //创建Key
    @Test
    public void genKey(){
        //生成key
        SecretKey secretKey = Keys.secretKeyFor(SignatureAlgorithm.HS256);
        //解析key
        String encode = Encoders.BASE64.encode(secretKey.getEncoded());
        System.out.println(encode);
    }


    //效验令牌
    @Test
    public  void parseToken(){
        String token ="eyJhbGciOiJIUzI1NiJ9.eyJuYW1lIjoiemhuYWdzYW4iLCJpZCI6NSwiZXhwIjoxNzE3MTQ4MDMxfQ.9v9ttOmA8TVrLJyDMIUhq4s4KaitkkMtwcgrmH7jzoM";
        JwtParser build = Jwts.parserBuilder().setSigningKey(key).build();
        Claims body = build.parseClaimsJws(token).getBody();
        System.out.println(body);

    }


}

需要在pom.xml中引用依赖

<!-- https://mvnrepository.com/artifact/io.jsonwebtoken/jjwt-api -->
<dependency>
   <groupId>io.jsonwebtoken</groupId>
   <artifactId>jjwt-api</artifactId>
   <version>0.11.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/io.jsonwebtoken/jjwt-impl -->
<dependency>
   <groupId>io.jsonwebtoken</groupId>
   <artifactId>jjwt-impl</artifactId>
   <version>0.11.5</version>
   <scope>runtime</scope>
</dependency>
<dependency>
   <groupId>io.jsonwebtoken</groupId>
   <artifactId>jjwt-jackson</artifactId> <!-- or jjwt-gson if Gson is preferred -->
   <version>0.11.5</version>
   <scope>runtime</scope>
</dependency>