public class TokenUtils {
    //设置过期时间30分钟
    private static final long EXPIRE_DATE = 30 * 60 * 1000;
    //token秘钥
    private static final String TOKEN_SECRET = "UG666UG666UG666";

    public static String getToken(User user) {

        String token = "";
        try {
            //过期时间
            Date date = new Date(System.currentTimeMillis() + EXPIRE_DATE);
            //秘钥及加密算法
            Algorithm algorithm = Algorithm.HMAC256(TOKEN_SECRET);
            //设置头部信息
            Map<String, Object> header = new HashMap<>();
            header.put("typ", "JWT");
            header.put("alg", "HS256");
            //携带username，password信息，生成签名
            token = JWT.create()
                    .withHeader(header)
                    .withClaim("username", user.getName())
                    .withClaim("password", user.getPwd())
                    .withExpiresAt(date)
                    .sign(algorithm);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        return token;
    }

    public static boolean verify(String token) {
        /**
         * @desc 验证token，通过返回true
         * @params [token]需要校验的串
         **/
        try {
            Algorithm algorithm = Algorithm.HMAC256(TOKEN_SECRET);
            JWTVerifier verifier = JWT.require(algorithm).build();
            DecodedJWT jwt = verifier.verify(token);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    public static String getUserName(String token) {
        /**
         * @desc 验证token，通过返回true
         * @params [token]需要校验的串
         **/
        try {
            Algorithm algorithm = Algorithm.HMAC256(TOKEN_SECRET);
            JWTVerifier verifier = JWT.require(algorithm).build();
            DecodedJWT jwt = verifier.verify(token);
            return jwt.getClaim("username").asString();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public static void main(String[] args) {
        User user = new User();
        String username ="ug666";
        String password = "123";
        user.setName(username);
        user.setPwd(password);
        String token = getToken(user);
        System.out.println(token);
        boolean b = verify("eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJwYXNzd29yZCI6IjEyMyIsImV4cCI6MTY3MjE0ODk2OCwidXNlcm5hbWUiOiJ1ZzY2NiJ9.MsMBmiHjBOn9r2QmpoQBROEWGTXaWuMVBBGuy8xunpg");
        System.out.println(b);

        System.out.println(getUserName(token));

        System.out.println(verify("eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJwYXNzd29yZCI6IjEyMyIsImV4cCI6MTY3MjE0ODk2OCwidXNlcm5hbWUiOiJ1ZzY2NiJ9.MsMBmiHjBOn9r2QmpoQBROEWGTXaWuMVBBGuy8xunpg"));

    }

}

需要添加jwt的maven依赖

<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.10.3</version>
</dependency>

配置拦截器InterceptorConfig

@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(JWTInterceptor())
                .addPathPatterns("/**") //拦截所以请求，通过判断token是否合法，来决定是否需要登录
                .excludePathPatterns("/user/login", "/user/logout", "/**/export", "/**/import", "/file/**");
    }

    @Bean
    public JWTInterceptor JWTInterceptor(){
        return new JWTInterceptor();
    }
}

编写JWTInterceptor拦截器

public class JWTInterceptor implements HandlerInterceptor {
    @Autowired
    private UserService userService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String token = request.getHeader("token");
        // 如果不是映射到方法直接通过
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        // 执行认证
        if (token != null){
            throw new ServiceException("NOTLOGIN");
        }
        // 获取token中的user id
        String userId;
        try{
            userId = TokenUtils.getUserName(token);
        }catch (JWTDecodeException j){
            throw new ServiceException("token验证失败");
        }
        //根据token中的userid查数据库
        User user = userService.getById(userId);
        if(user == null){
            throw new ServiceException("用户不存在，请重新登录");
        }
        //用户密码加签验证token
        try{
            TokenUtils.verify(token);
        }catch (JWTVerificationException j){
            throw new ServiceException("token验证失败,请重新登录");
        }

        return true;
    }
}