spring mvc与 spring boot图片下载

//ͼƬÏÂÔØ
  @RequestMapping(value = "/merchant/activity/download.json")
  public String download(HttpServletResponse response,
      HttpServletRequest request) throws Exception {
    String url = "https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1535512873&di=4b2073fa8a223bf04add8fbdba5c1291&imgtype=jpg&er=1&src=http%3A%2F%2Fimg.zcool.cn%2Fcommunity%2F0117e2571b8b246ac72538120dd8a4.jpg%401280w_1l_2o_100sh.jpg";
   download(url, "²âÊÔÄÚÈÝ", response);
    return null;
  }
  
  
  @Override
  public void download(String imagePath, String imageName,HttpServletResponse response) throws Exception {
    /*List<String> suffixList = Arrays.asList(Constants.FILETYPE_DOWNLOAD_IMG);*/
    String svgsuffix = ".png";

    if(imagePath!=""&&!imagePath.equals(null)){
      BufferedInputStream in = null;
      BufferedOutputStream out = null;
      try {
        URL url = new URL(imagePath);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setConnectTimeout(5 * 1000);
        conn.setRequestMethod("GET");
        conn.setRequestProperty(
            "Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, "
                + "application/x-shockwave-flash, application/xaml+xml, "
                + "application/vnd.ms-xpsdocument, application/x-ms-xbap, "
                + "application/x-ms-application, application/vnd.ms-excel, "
                + "application/vnd.ms-powerpoint, application/msword, */*");
        conn.setRequestProperty("Accept-Language", "zh-CN");