java spring boot 小程序二维码 base64

    public static String httpPostWithJSON(String url, String json) throws Exception {
        String result = null;
        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost httpPost = new HttpPost(url);
        httpPost.addHeader(HTTP.CONTENT_TYPE, "application/json");
        //参数
        StringEntity se = new StringEntity(json,"utf-8");
        se.setContentType("application/json");
        se.setContentEncoding("UTF-8");
        //设置请求参数
        httpPost.setEntity(se);
        //发送请求
        HttpResponse response = httpClient.execute(httpPost);
        if (response != null) {
          HttpEntity resEntity =  response.getEntity();
         InputStream instreams = resEntity.getContent();

        result = getBase64FromInputStream(instreams);
        result = "data:image/png;base64,"+result;
        }
        httpPost.abort();
        return result;
    }
 
 /*
  * @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 String saveToImgByInputStream(InputStream instreams, String imgPath, String imgName) {
        String path = "";
        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 {
        try {
         instreams.close();
        } catch (IOException e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
        }
        }
    }
   return path;
 }
 
         /**
   *
   * 转base64
   *
   * */
    public static String getBase64FromInputStream(InputStream in) {
        // 将图片文件转化为字节数组字符串，并对其进行Base64编码处理
        byte[] data = null;
        // 读取图片字节数组
        try {
        ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
        byte[] buff = new byte[100];
        int rc = 0;
        while ((rc = in.read(buff, 0, 100)) > 0) {
         swapStream.write(buff, 0, rc);
        }
        data = swapStream.toByteArray();
        } catch (IOException e) {
        e.printStackTrace();
        } finally {
        if (in != null) {
         try {
           in.close();
         } catch (IOException e) {
           e.printStackTrace();
         }
        }
        }
        return new String(Base64.encodeBase64(data));
    }