埠開啟方式：

centos7下跟舊版本有些不同：
firewall-cmd –zone=public –add-port=20/tcp –permanent
firewall-cmd –zone=public –add-port=21/tcp –permanent
firewall-cmd –zone=public –add-port=22/tcp –permanent
firewall-cmd –zone=public –add-port=30000-35000/tcp –permanent
重啟防火牆：
systemctl restart firewalld.service

在Java程式碼中構建ftp上傳中可增加：

ftp.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));

檢視各種上傳狀態：

CWD /home/ftpuser/ftp/images
250 Directory successfully changed.
TYPE
200 Switching to Binary mode.
PORT 192,168,0,7,22,31
200 PORT command successful. Consider using PASV.
STOR 3.jpg
425 Failed to> establish connection.

以上錯誤需要在上傳設定時：ftp.enterLocalPassiveMode();

Java FTP 報錯 ：Permission denied: recv failed 關閉本機防火牆解決

FTP上傳成功返回：553 Could not create file 上傳者使用者對目標資料夾的許可權設定