public class GetQcCodeUtil {
    
    //获取二维码路径
    private static final String WxCode_URL = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=ACCESS_TOKEN";
    //图片储存路径
    private static final String SAVE_PATH = "";
    
    /**
     * 获取二维码
     * @param accessToken
     * @param fileName 文件名称
     * @param param  二维码参数
     * @return
     */
    public static String getminiqrQr(String accessToken,String fileName,String param) {
        File file = new File(SAVE_PATH);
        if (!file.exists()) {
            file.mkdirs();// 创建文件根目录
        }
        String savePath = file.getPath() + File.separator + fileName;
        String qrCode = SAVE_PATH + File.separator + fileName;
        if (qrCode.contains("\\")) {
            qrCode = qrCode.replace("\\", "/");
        }
        try
        {
            String wxCodeURL = WxCode_URL.replace("ACCESS_TOKEN",accessToken);
            URL url = new URL(wxCodeURL);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");// 提交模式
            httpURLConnection.setConnectTimeout(10000);//连接超时 单位毫秒
            httpURLConnection.setReadTimeout(2000);//读取超时 单位毫秒
            // 发送POST请求必须设置如下两行
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream());
            // 发送请求参数
            JSONObject paramJson = new JSONObject();
            paramJson.put("scene", param);//参数
            paramJson.put("page", ""); //若小程序暂未发布 带page参数无作用
            paramJson.put("width", 400);//生成二维码的大小
            paramJson.put("is_hyaline", true);
            paramJson.put("auto_color", true);
            printWriter.write(paramJson.toString());
            // flush输出流的缓冲
            printWriter.flush();
            //开始获取数据
            BufferedInputStream bis = new BufferedInputStream(httpURLConnection.getInputStream());
            OutputStream os = new FileOutputStream(new File(savePath));
            int len;
            byte[] arr = new byte[1024];
            while ((len = bis.read(arr)) != -1)
            {
                os.write(arr, 0, len);
                os.flush();
            }
            os.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        return qrCode;
    }


    public static void main(String[] args) {
        String token = "";//若不知道怎么获取 请查看 https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/access-token/auth.getAccessToken.html
        System.out.println(getminiqrQr(token,FormatTimeUtil.getTimeMillis()+"图片名称","参数"));
    }
}