@GetMapping("getImage")
    public void getImage(HttpServletResponse response) throws Exception {
        //new一个URL对象
        URL url = new URL("ftp://ftpuser:123456qwe@192.168.1.126:21/2020/01/01/0001.jpg");
        //打开链接
        URLConnection conn = url.openConnection();
        //超时响应时间为5秒
        conn.setConnectTimeout(5 * 1000);
        //通过输入流获取图片数据
        InputStream inStream = conn.getInputStream();
        //得到图片的二进制数据，以二进制封装得到数据，具有通用性
        byte[] data = readInputStream(inStream);
        //new一个文件对象用来保存图片，默认保存当前工程根目录
        //File imageFile = new File("D:\\0001.jpg");
        //创建输出流
        //FileOutputStream outStream = new FileOutputStream(imageFile);
        OutputStream outStream=response.getOutputStream();//输出数据
        //写入数据
        outStream.write(data);
        outStream.flush();
        //关闭输出流
        outStream.close();
        
    }
 
    public static byte[] readInputStream(InputStream inStream) throws Exception {
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        //创建一个Buffer字符串
        byte[] buffer = new byte[4096];
        //每次读取的字符串长度，如果为-1，代表全部读取完毕
        int len = 0;
        //使用一个输入流从buffer里把数据读取出来
        while ((len = inStream.read(buffer)) != -1) {
            //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
            outStream.write(buffer, 0, len);
        }
        //关闭输入流
        inStream.close();
        //把outStream里的数据写入内存
        return outStream.toByteArray();
    }