java 判断用户是否关注了公众号

1.获取token

    public String  getToken(){
        try {
            HttpClient client = HttpClients.createDefault();
            String tokenUrl = MessageFormat.format("https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={0}&secret={1}", APP_ID, APP_SECRET);
            HttpGet request = new HttpGet(tokenUrl);
            HttpResponse response = client.execute(request);
            JSonObject object = getResponseJson(response);
            if (object == null) {
                return null;
            }
            return ObjectUtils.isEmpty(object) ? null : object.getString("access_token");
        }catch (Exception e){ log.info(e.getMessage()); }
        return null;
    }

2.获取用户openId

    // code前端传；type：1.公众号 2.小程序
    public UserOpenIdDto getUserOpenId(String code,Integer type ) {
        String resultStr;
        UserOpenIdDto userOpenIdDto = new UserOpenIdDto();
        try {
            if(OpenIdTypeEnum.TYPE_PUBLIC.getCode().equals(type)){
                //公众号发送请求
                resultStr = wxUtils.executeHttpGet("https://api.weixin.qq.com/sns/oauth2/access_token?appid={0}&secret={1}&code={2}&grant_type=authorization_code", publicappid, publicSecret, code);
            }else {
                //小程序发送请求
                resultStr = wxUtils.executeHttpGet("https://api.weixin.qq.com/sns/jscode2session?appid={0}&secret={1}&js_code={2}&grant_type=authorization_code", uappid, uSecret, code);
            }
            //解析响应
            JSonObject jsonObject = JSONObject.parseObject(resultStr);
            if (ObjectUtils.isEmpty(jsonObject)){
                throw new CommonException(ErrorCodeEnum.LOGIN_GET_THIRD_PARTY_USER_INFO_FAIL);
            }
            userOpenIdDto.setOpenId(jsonObject.getString("openid"));
            userOpenIdDto.setUnionId(jsonObject.getString("unionid"));
        } catch (IOException e) {
            throw new CommonException(ErrorCodeEnum.LOGIN_GET_THIRD_PARTY_USER_INFO_FAIL);
        }
        return userOpenIdDto;
    }

2-1 执行get url

    public String executeHttpGet(String url,String appId,String secret,String code) throws IOException {

        String formatUrl = MessageFormat.format(url,appId,secret,code);

        HttpClient client = HttpClients.createDefault();
        HttpGet request = new HttpGet(formatUrl);
        HttpResponse response = client.execute(request);
        return readResponse(response);
    }

3.查询用户是否关注了公众号

    
    public  boolean userIsFollowPublic(String token,String openid){
        Integer subscribe = 0;
        String url = "https://api.weixin.qq.com/cgi-bin/user/info?access_token={0}&openid={1}&lang=zh_CN";
        url = MessageFormat.format(url,token,openid);
        try {
            URL urlGet = new URL(url);
            HttpURLConnection http = (HttpURLConnection) urlGet.openConnection();
            http.setRequestMethod("GET"); // 必须是get方式请求
            http.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
            http.setDoOutput(true);
            http.setDoInput(true);
            http.connect();
            InputStream is = http.getInputStream();
            int size = is.available();
            byte[] jsonBytes = new byte[size];
            is.read(jsonBytes);
            String message = new String(jsonBytes, "UTF-8");
            JSonObject demoJson = JSONObject.parseObject(message);
            subscribe = demoJson.getIntValue("subscribe"); // 此字段为关注字段  关注为1 未关注为0
            is.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return 1 == subscribe;
    }