#vulnerable code 
                                private ResponseEntity<String> mina(IPageData pd, JSONObject paramIn, JSONObject paramOut, String userId, List<OwnerAppUserDto> ownerAppUserDtos) {

        ResponseEntity<String> responseEntity = null;
        //查询微信信息
        pd = PageData.newInstance().builder(userId, "", "", pd.getReqData(),
                "", "", "", "",
                pd.getAppId());
        responseEntity = this.callCenterService(restTemplate, pd, "",
                ServiceConstant.SERVICE_API_URL + "/api/smallWeChat.listSmallWeChats?appId="
                        + paramIn.getString("appId") + "&page=1&row=1", HttpMethod.GET);

        if (responseEntity.getStatusCode() != HttpStatus.OK) {
            return responseEntity;
        }
        JSONObject smallWechatObj = JSONObject.parseObject(responseEntity.getBody().toString());
        JSONArray smallWeChats = smallWechatObj.getJSONArray("smallWeChats");
        String appId = wechatAuthProperties.getAppId();
        String secret = wechatAuthProperties.getSecret();
        if (smallWeChats.size() > 0) {
            appId = smallWeChats.getJSONObject(0).getString("appId");
            secret = smallWeChats.getJSONObject(0).getString("appSecret");
        }

        String code = paramIn.getString("code");
        String urlString = "?appid={appId}&secret={secret}&js_code={code}&grant_type={grantType}";
        String response = outRestTemplate.getForObject(
                wechatAuthProperties.getSessionHost() + urlString, String.class,
                appId,
                secret,
                code,
                wechatAuthProperties.getGrantType());

        logger.debug("wechatAuthProperties:" + JSONObject.toJSONString(wechatAuthProperties));

        logger.debug("微信返回报文：" + response);

        //Assert.jsonObjectHaveKey(response, "errcode", "返回报文中未包含 错误编码，接口出错");
        JSONObject responseObj = JSONObject.parseObject(response);

        if (responseObj.containsKey("errcode") && !"0".equals(responseObj.getString("errcode"))) {
            throw new IllegalArgumentException("微信验证失败，可能是code失效" + responseObj);
        }

        String openId = responseObj.getString("openid");

        OwnerAppUserDto ownerAppUserDto = judgeCurrentOwnerBind(ownerAppUserDtos, OwnerAppUserDto.APP_TYPE_WECHAT_MINA);

        //说明 当前的openId 就是最新的
        if (ownerAppUserDto != null && openId.equals(ownerAppUserDto.getOpenId())) {
            return new ResponseEntity<>(paramOut.toJSONString(), HttpStatus.OK);
        }

        OwnerAppUserDto tmpOwnerAppUserDto = new OwnerAppUserDto();
        ownerAppUserDto.setOpenId(openId);
        ownerAppUserDto.setAppType(OwnerAppUserDto.APP_TYPE_WECHAT_MINA);
        if (ownerAppUserDto != null) {
            ownerAppUserDto.setAppUserId(tmpOwnerAppUserDto.getAppUserId());
            ownerAppUserDto.setCommunityId(tmpOwnerAppUserDto.getCommunityId());
        } else {
            ownerAppUserDto.setOldAppUserId(ownerAppUserDtos.get(0).getAppUserId());
            ownerAppUserDto.setAppUserId("-1");
            ownerAppUserDto.setCommunityId(ownerAppUserDtos.get(0).getCommunityId());
        }
        //查询微信信息
        pd = PageData.newInstance().builder(userId, "", "", pd.getReqData(),
                "", "", "", "",
                pd.getAppId());

        super.postForApi(pd, ownerAppUserDto, ServiceCodeConstant.REFRESH_APP_USER_BINDING_OWNER_OPEN_ID,
                OwnerAppUserDto.class);
        return new ResponseEntity<>(paramOut.toJSONString(), HttpStatus.OK);
    } 
                            #location 54 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                private ResponseEntity<String> mina(IPageData pd, JSONObject paramIn, JSONObject paramOut, String userId, List<OwnerAppUserDto> ownerAppUserDtos) {

        ResponseEntity<String> responseEntity = null;
        //查询微信信息
        pd = PageData.newInstance().builder(userId, "", "", pd.getReqData(),
                "", "", "", "",
                pd.getAppId());
        responseEntity = this.callCenterService(restTemplate, pd, "",
                ServiceConstant.SERVICE_API_URL + "/api/smallWeChat.listSmallWeChats?appId="
                        + paramIn.getString("appId") + "&page=1&row=1", HttpMethod.GET);

        if (responseEntity.getStatusCode() != HttpStatus.OK) {
            return responseEntity;
        }
        JSONObject smallWechatObj = JSONObject.parseObject(responseEntity.getBody().toString());
        JSONArray smallWeChats = smallWechatObj.getJSONArray("smallWeChats");
        String appId = wechatAuthProperties.getAppId();
        String secret = wechatAuthProperties.getSecret();
        if (smallWeChats.size() > 0) {
            appId = smallWeChats.getJSONObject(0).getString("appId");
            secret = smallWeChats.getJSONObject(0).getString("appSecret");
        }

        String code = paramIn.getString("code");
        String urlString = "?appid={appId}&secret={secret}&js_code={code}&grant_type={grantType}";
        String response = outRestTemplate.getForObject(
                wechatAuthProperties.getSessionHost() + urlString, String.class,
                appId,
                secret,
                code,
                wechatAuthProperties.getGrantType());

        logger.debug("wechatAuthProperties:" + JSONObject.toJSONString(wechatAuthProperties));

        logger.debug("微信返回报文：" + response);

        //Assert.jsonObjectHaveKey(response, "errcode", "返回报文中未包含 错误编码，接口出错");
        JSONObject responseObj = JSONObject.parseObject(response);

        if (responseObj.containsKey("errcode") && !"0".equals(responseObj.getString("errcode"))) {
            throw new IllegalArgumentException("微信验证失败，可能是code失效" + responseObj);
        }

        String openId = responseObj.getString("openid");

        OwnerAppUserDto ownerAppUserDto = judgeCurrentOwnerBind(ownerAppUserDtos, OwnerAppUserDto.APP_TYPE_WECHAT_MINA);

        //说明 当前的openId 就是最新的
        if (ownerAppUserDto != null && openId.equals(ownerAppUserDto.getOpenId())) {
            return new ResponseEntity<>(paramOut.toJSONString(), HttpStatus.OK);
        }

        OwnerAppUserDto tmpOwnerAppUserDto = new OwnerAppUserDto();
        tmpOwnerAppUserDto.setOpenId(openId);
        tmpOwnerAppUserDto.setAppType(OwnerAppUserDto.APP_TYPE_WECHAT_MINA);
        if (ownerAppUserDto != null) {
            tmpOwnerAppUserDto.setAppUserId(ownerAppUserDto.getAppUserId());
            tmpOwnerAppUserDto.setCommunityId(ownerAppUserDto.getCommunityId());
        } else {
            tmpOwnerAppUserDto.setOldAppUserId(ownerAppUserDtos.get(0).getAppUserId());
            tmpOwnerAppUserDto.setAppUserId("-1");
            tmpOwnerAppUserDto.setCommunityId(ownerAppUserDtos.get(0).getCommunityId());
        }
        //查询微信信息
        pd = PageData.newInstance().builder(userId, "", "", pd.getReqData(),
                "", "", "", "",
                pd.getAppId());

        super.postForApi(pd, tmpOwnerAppUserDto, ServiceCodeConstant.REFRESH_APP_USER_BINDING_OWNER_OPEN_ID,
                OwnerAppUserDto.class);
        return new ResponseEntity<>(paramOut.toJSONString(), HttpStatus.OK);
    }