<dependencies>
    <dependency>
        <groupId>cn.hutool</groupId>
        <artifactId>hutool-all</artifactId>
        <version>5.5.1</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.2.33</version>
    </dependency>
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt</artifactId>
        <version>0.9.1</version>
    </dependency>
</dependencies>

package com.demo.auth.utils;


import io.jsonwebtoken.*;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.util.*;


public class JwtUtil {
    public static final long JWT_TTL = 1000L * 60 * 60 * 24; // 24小時
    public static final String JWT_KEY = "qx";


    public static String createJWT(String subject) {
        return getJwtBuilder(subject, null, UUID.randomUUID().toString().replace("-", "")).compact();
    }


    public static String createJWT(String subject, Long ttlMillis) {
        return getJwtBuilder(subject, ttlMillis, UUID.randomUUID().toString()).compact();
    }


    private static JwtBuilder getJwtBuilder(String subject, Long ttlMillis, String uuid) {
        long nowMillis = System.currentTimeMillis();
        long expMillis = (ttlMillis != null ? nowMillis + ttlMillis : nowMillis + JWT_TTL);
        SecretKey secretKey = generalKey();
        return Jwts.builder()
                .setId(uuid)
                .setSubject(subject)
                .setIssuer("icoderoad")
                .setIssuedAt(new Date(nowMillis))
                .setExpiration(new Date(expMillis))
                .signWith(SignatureAlgorithm.HS256, secretKey);
    }


    public static Claims parseJWT(String jwt) throws Exception {
        return Jwts.parser()
                .setSigningKey(generalKey())
                .parseClaimsJws(jwt)
                .getBody();
    }


    public static SecretKey generalKey() {
        byte[] key = Base64.getDecoder().decode(JWT_KEY);
        return new SecretKeySpec(key, 0, key.length, "AES");
    }


    public static Date getExpiration(String jwt) {
        try {
            return parseJWT(jwt).getExpiration();
        } catch (Exception e) {
            throw new RuntimeException("Token 解析失敗", e);
        }
    }
}

public class AuthInterceptor implements HandlerInterceptor {


    private static final long REFRESH_THRESHOLD = 1000L * 60 * 5; // 剩余5分鐘內(nèi)刷新


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {


        String token = request.getHeader("Authorization");
        if (StringUtils.isEmpty(token)) {
            throw new RuntimeException("未登錄");
        }


        Claims claims = JwtUtil.parseJWT(token);
        long now = System.currentTimeMillis();
        long exp = claims.getExpiration().getTime();


        if (exp - now < REFRESH_THRESHOLD) {
            String newToken = JwtUtil.createJWT(claims.getSubject());
            response.setHeader("X-Token-Refresh", newToken);
        }


        return true;
    }
}

axios.interceptors.response.use(response => {
    const newToken = response.headers['x-token-refresh'];
    if (newToken && newToken !== localStorage.getItem('access_token')) {
        localStorage.setItem('access_token', newToken);
    }
    return response;
}, error => {
    // 處理401
    if (error.response.status === 401) {
        // 可以保存草稿后跳轉(zhuǎn)登錄
    }
    return Promise.reject(error);
});