ftp读取图片并转Base64

public String download(String ftpUrl,String sfzh){
       FTPClient ftpClient = new FTPClient();
       InputStream inputStream = null;
       String re=null;
       try {
           ftpClient.connect(ftp_ip,ftp_port);
           ftpClient.login(ftp_username, ftp_password);
           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();
           }
           //跳转到指定目录
           ftpClient.changeWorkingDirectory(ftpUrl);
           //5.遍历下载的目录
           FTPFile[] fs = ftpClient.listFiles();
           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 (inputStream != null) {
               byte[] data=null;
               data=new byte[inputStream.available()];
               BASE64Encoder encoder=new BASE64Encoder();
               re=encoder.encode(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;
   }