环境：php8.3\tp8.1\firebase-jwt6.1

app\api\middleware\CheckJwt;

<?php
declare (strict_types = 1);

namespace app\api\middleware;
use app\api\lib\util\JwtUtil;
use Closure;
use think\Request;
use think\Response;

class CheckJwt
{
    /**
     * 处理请求
     *
     * @param Request $request
     * @param Closure       $next
     * @return Response
     */
    public function handle(Request $request, Closure $next): Response
    {
        $auth = $request->header('authorization');
        if ($auth == null) {
            return $next($request);
        }
        $token = str_replace("Bearer ","",$auth);
        $jUtil = new JwtUtil();
        $res = $jUtil->verifyJwt($token);
        if (isset($res['code']) && isset($res['userId']) && $res['code'] == 0 && is_int($res['userId'])) {
            $userId = $res['userId'];
            $request->auth = $userId;
        } else {
            $request->auth = 0;
        }
        return $next($request);
    }
}

app\api\lib\util\JwtUtil;

<?php

namespace app\api\lib\util;

use Firebase\JWT\ExpiredException;
use Firebase\JWT\JWT;
use Firebase\JWT\Key;

class JwtUtil
{
    private string $signKey = "quwei";
    private int $timeMinutes = 5;

    /**
     * 根据json web token设置的规则生成token
     * @param $userId
     * @return string
     */
    public function createJwt($userId):string
    {
        $key = md5($this->signKey); //jwt的签发**，验证token的时候需要用到
        $time = time(); //签发时间
        $expire = $time + $this->timeMinutes*60; //过期时间
        $token = array(
            "userId" => $userId,
            "iss" => "http://www.quweiie.cn/",//签发组织
            "aud" => "lhd", //签发作者
            "iat" => $time,    //签发时间
            "nbf" => $time,    //生效时间
            "exp" => $expire    //过期时间
        );
        return JWT::encode($token, $key,'HS256');
    }

    /**
     * 验证token
     * @param $token
     * @return array
     */
    public function verifyJwt($token): array
    {
        $key = md5($this->signKey); //jwt的签发**，验证token的时候需要用到
        try{
            $jwtAuth = json_encode(JWT::decode($token, new Key($key, 'HS256')));
            $authInfo = json_decode($jwtAuth,true);
            if (!$authInfo['userId']){
                return ['code'=>0,'msg'=>"用户不存在"];
            }
            return ['code'=>0,'userId'=>$authInfo['userId'],'msg'=>"ok"];
        }catch (ExpiredException $e){
            return ['code'=>0,'msg'=>"token过期"];
        }catch (\Exception $e){
            return ['code'=>0,'msg'=>$e->getMessage()];
        }
    }
}

app\api\controller\auth.php

<?php

namespace app\api\controller;

use app\api\lib\util\JwtUtil;
use think\response\Json;
use think\facade\Db;

class Auth
{
    public function login(): Json
    {
        $username = input('post.username');
        $password = input('post.password');
        try {
            $result = Db::name('users')->where(['username'=>$username, 'password'=>$password])->find();
            if (!empty($result)) {
                $userId = $result['id'];
                $jUtil = new JwtUtil();
                $token = $jUtil->createJwt($userId);
            } else {
                return json(['code'=>500, 'msg'=>'该用户不存在']);
            }
        } catch (\Exception $e) {
            return json(['code'=>500, 'msg'=>$e->getMessage()]);
        }
        
        return json(['code'=>200, 'msg'=>'success','token'=>$token]);
    }

    public function info(): Json
    {
        if (request()->auth > 0) {
            $status = "已登录";
        } else {
            $status = "未登录";
        }

        $info = [
            'userId'=>request()->auth,
            'status'=>$status,
        ];
        return json($info);
    }
}

这是完整的步骤，欢迎大家指正。