/*
     * 获取二维码
　　　* 这里的 post 方法 为 json post【重点】
     */
    @RequestMapping("/getCode")
    public ResponseMsg getCodeM(HttpServletRequest request) throws Exception {
        
        String imei ="867186032552993";
        String page="page/msg_waist/msg_waist";
        String token = getToken();   // 得到token
        
        Map<String, Object> params = new HashMap<>();
        params.put("scene", imei);  //参数
        params.put("page", "page/msg_waist/msg_waist"); //位置
        params.put("width", 430);

        CloseableHttpClient  httpClient = HttpClientBuilder.create().build();

        HttpPost httpPost = new HttpPost("https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token="+token);  // 接口
        httpPost.addHeader(HTTP.CONTENT_TYPE, "application/json");
        String body = JSON.toJSONString(params);           //必须是json模式的 post      
        StringEntity entity;
        entity = new StringEntity(body);
        entity.setContentType("image/png");

        httpPost.setEntity(entity);
        HttpResponse response;

        response = httpClient.execute(httpPost);
        InputStream inputStream = response.getEntity().getContent();
        String name = imei+".png";
        saveToImgByInputStream(inputStream,"D:\\",name);  //保存图片
        return null;
    }






    /*
     * 获取 token
　　　* 普通的 get 可获 token
     */
    public String getToken() {
        try {

            Map<String, String> map = new LinkedHashMap<String, String>();
            map.put("grant_type", grant_type);
            map.put("appid", appid);
            map.put("secret", secret);

            String rt = HttpUtils.sendGet(TOKEN_URL, map);
            
            System.out.println(rt);
            JSONObject json = JSONObject.parseObject(rt);

            if (json.getString("access_token") != null || json.getString("access_token") != "") {
                return json.getString("access_token");
            } else {
                return null;
            }
} catch (Exception e) {
            log.error("# 获取 token 出错... e:" + e);
            e.printStackTrace();
            return null;
        }

    }




     /**
     * 将二进制转换成文件保存
     * @param instreams 二进制流
     * @param imgPath 图片的保存路径
     * @param imgName 图片的名称
     * @return 
     *      1：保存正常
     *      0：保存失败
     */
    public static int saveToImgByInputStream(InputStream instreams,String imgPath,String imgName){
        int stateInt = 1;
        if(instreams != null){
            try {
                File file=new File(imgPath,imgName);//可以是任何图片格式.jpg,.png等
                FileOutputStream fos=new FileOutputStream(file);
                byte[] b = new byte[1024];
                int nRead = 0;
                while ((nRead = instreams.read(b)) != -1) {
                    fos.write(b, 0, nRead);
                }
                fos.flush();
                fos.close();                
            } catch (Exception e) {
                stateInt = 0;
                e.printStackTrace();
            } finally {
            }
        }
        return stateInt;
    }