java从ftp服务器拉取图片转化为base64或 从FTP下载图片返回文件流在页面显示图片

ftp默认端口21
1转化为base64

    public static  String download(String ftpUrl,int  index){
        //ftpUrl :文件夹路径  afzh:图片路径
        FTPClient ftpClient = new FTPClient();
        int temp=index+1;
        InputStream inputStream = null;
        String re=null;
        try {
            ftpClient.connect(ip,21);//ip地址，端口号
            ftpClient.login("", "");//账户，密码
            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
            //是否成功登录服务器
            int reply = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(reply)) {
                ftpClient.disconnect();
            }
             ftpClient.enterLocalPassiveMode();--重要 不然linux上不行
            //跳转到指定目录
            ftpClient.changeWorkingDirectory(ftpUrl);
            //5.遍历下载的目录
            FTPFile[] fs = ftpClient.listFiles();
            //数组下标
            int count=0;
            String picType;
            for (FTPFile ff : fs){
                //解决中文乱码问题，两次解码
                byte[] bytes=ff.getName().getBytes("iso-8859-1");
                String fileName=new String(bytes,"utf-8");
                /*if(sfzh.equals(fileName)){
                    inputStream = ftpClient.retrieveFileStream(fileName);
                }*/
                 if(count==temp){
                    inputStream = ftpClient.retrieveFileStream(fileName);

                }
                 count++;
            }
            if (inputStream != null) {
                byte[] data=null;
                ByteArrayOutputStream outStream =new ByteArrayOutputStream();
                data=new byte[inputStream.available()];
                int len=0;
                while((len=inputStream.read(data))!=-1){
                    outStream.write(data,0,len);
                }
                data=outStream.toByteArray();
                Base64.Encoder encoder= Base64.getEncoder();
                re=encoder.encodeToString(data);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            if(ftpClient.isConnected()){
                try{
                    ftpClient.disconnect();
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
            if(null != inputStream){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return re;
    }

2流下载图片

  @GetMapping("/xx/getXXX")
 public static  void download1(String ftpUrl,int  index,HttpServletResponse response){
        //ftpUrl :文件夹路径  afzh:图片路径
        FTPClient ftpClient = new FTPClient();
        int temp=index+1;
        InputStream inputStream = null;
        String re=null;
        OutputStream outStream  = null;
        try {
            ftpClient.connect("",);//ip地址，端口号
            ftpClient.login("", "");//账户，密码
            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
            //是否成功登录服务器
            int reply = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(reply)) {
                ftpClient.disconnect();
            }
            ftpClient.enterLocalPassiveMode();--重要 不然linux上不行
            //跳转到指定目录
            ftpClient.changeWorkingDirectory(ftpUrl);
            //5.遍历下载的目录
            FTPFile[] fs = ftpClient.listFiles();
            //数组下标
            int count=0;
            String picType;
            for (FTPFile ff : fs){
                //解决中文乱码问题，两次解码
                byte[] bytes=ff.getName().getBytes("iso-8859-1");
                String fileName=new String(bytes,"utf-8");
                if(count==temp){
                    inputStream = ftpClient.retrieveFileStream(fileName);
                    picType = fileName.split("\\.")[1];
                    BufferedImage bufImg = null;
                    bufImg = ImageIO.read(inputStream);
                    outStream = response.getOutputStream();
                    ImageIO.write(bufImg,  picType, outStream);
                    break;
                }
                count++;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            if(ftpClient.isConnected()){
                try{
                    ftpClient.disconnect();
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
            if(null != inputStream){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }

html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <img src="http://ip:port/xx/getXXX?ftpUrl=xxx&index=x"   width="400" height="266" />
</body>
</html>