errcode:40001 errmsg:invalid credential, access_token is invalid or not latest hint

前段时间水运头条线上分享功能调用微信接口获取小程序码时,报errcode:40001,并且获取小程序码时有时报错有时不报错.可是我本地和测试环境并没有发生这种情况.于是乎就去百度微信errcode:40001代表的含义(获取access_token时Secret错误，或者access_token无效)

微信接口状态码的返回含义时,大致知道原因了.本地和测试环境只有一台机器,我的本地和测试环境调用微信接口获取access_token时,是用static修饰的变量接收的,所以access_token不会实时刷新,只有过了有效期才会重新去刷新,这时获取access_token是不会出现token失效的.

private static final Logger LOGGER = LoggerFactory.getLogger(WeixinUtils.class);
private static String accessToken = null;
private static long getAccessTokenTime;
private static int expires_in;

public static String getAccessToken(ConfigurationService configurationService) {
    accessToken = configurationService.get("accessToken");
    if (accessToken == null) {
        return doAccessToken(configurationService);
    } else {
        getAccessTokenTime = Long.parseLong(configurationService.get("getAccessTokenTime"));
        long totalSeconds = (System.currentTimeMillis() - getAccessTokenTime) / 1000;
        expires_in = Integer.parseInt(configurationService.get("expires_in"));
            if (totalSeconds > expires_in) {
            return doAccessToken(configurationService);
        } else {
            return accessToken;
        }
    }
}

private static String doAccessToken() {
    String url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&"
            + "appid=" + xxxxxxxxxxxx
            + "&secret=" + xxxxxxxxxx;

    JSONObject jsonObject = HttpUtil.httpGet(url);
    if (jsonObject == null) {
        LOGGER.error("Failed to get access_token, response is null.");
        return null;
    }
    Object errorCode = jsonObject.get("errcode");
    if (errorCode != null) {
        LOGGER.error("Failed to get access_token. Error code : '{}'", errorCode.toString());
        return null;
    }
    accessToken = jsonObject.getString("access_token");
    expires_in = jsonObject.getInt("expires_in");
    getAccessTokenTime = System.currentTimeMillis();

    return accessToken;
}

可是线上环境有负载均衡请求会被分配到多台机器上去执行,每台机器都会去获取一次access_token，根据微信开发文档说明多次获取access_token时,老token的有效期只有5分钟.这样过了5分钟后,老token就失效了.可是有台机器存储的token还是老token,失效时间还有115分钟才会重新获取token，在这期间这台机器调用这个接口就会报errorcode:40001.

解决方法:采用分布式缓存来缓存access_token,这样就能保证线上每台机器都是同一个access_token.