使用Java在CentOS ec2实例上进行FTP

从服务器（FileZilla，设置为被动模式）到部署在CentOS ec2实例上的web应用程序的FTP传输出现问题。 通过从实例手动测试wget和ftp，我们能够进行身份验证、更改目录和获取文件。但是，我们部署在ec2上的webapp不会获取文件，尽管它会成功地进行身份验证和导航。 我们的应用程序中的FTP上传在我们的局域网上运行良好，并且在外部进行测试（无线连接上的开发人员笔记本电脑，无VPN）

作为这一部分，我们已经编写了更为集中的单元测试，并且目前正在复制以下失败和成功案例，从ec2（失败）和非ec2（成功）部署：

FileZilla服务器日志文件在登录、用户、PASS和CWD方面都是相同的，但一旦传输开始就不同了

成功案例如下：

(000216) 8/28/2012 10:47:20 AM - (not logged in) (external IP)> Connected, sending welcome message...
(000216) 8/28/2012 10:47:20 AM - (not logged in) (external IP)> 220-FileZilla Server version 0.9.24 beta
(000216) 8/28/2012 10:47:20 AM - (not logged in) (external IP)> 220 Connected to server FTP!
(000216) 8/28/2012 10:47:20 AM - (not logged in) (external IP)> USER ftpUser
(000216) 8/28/2012 10:47:20 AM - (not logged in) (external IP)> 331 Password required for ftpUser
(000216) 8/28/2012 10:47:20 AM - (not logged in) (external IP)> PASS *********
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> 230 Logged on
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> TYPE I
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> 200 Type set to I
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> CWD DPS
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> 250 CWD successful. "/DPS" is current directory.
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> CWD DP276
(000216) 8/28/2012 10:47:20 AM - ftpUser (external IP)> 250 CWD successful. "/DPS/DP276" is current directory.
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> PASV ALL
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> 227 Entering Passive Mode (FTP Server IP4,190)
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> PASV
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> 227 Entering Passive Mode (FTP Server IP4,191)
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> RETR sales.txt
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> 150 Connection accepted
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> 226 Transfer OK
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> QUIT
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> 221 Goodbye
(000216) 8/28/2012 10:47:21 AM - ftpUser (external IP)> disconnected.

故障案例：

(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> Connected, sending welcome message...
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> 220-FileZilla Server version 0.9.24 beta
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> 220 Connected to server FTP!
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> USER ftpUser
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> 331 Password required for ftpUser
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> PASS *********
(000217) 8/28/2012 11:25:11 AM - ftpUser (ec2 Instance IP)> 230 Logged on
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> TYPE I
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 200 Type set to I
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> CWD DPS
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 250 CWD successful. "/DPS" is current directory.
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> CWD DP276
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 250 CWD successful. "/DPS/DP276" is current directory.
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> EPSV ALL
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 229 Entering Extended Passive Mode (|||1318|)
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> EPSV
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 229 Entering Extended Passive Mode (|||1319|)
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> EPRT |1|ec2 internal IP|37245|
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 200 Port command successful
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> RETR products.txt
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 150 Opening data channel for file transfer.
(000217) 8/28/2012 11:25:23 AM - ftpUser (ec2 Instance IP)> 425 Can't open data connection.

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尝试在测试方法结束时调用out.flush（）或out.close（）。主线程似乎正在消亡，而没有将内容刷新到服务器

成功案例使用被动模式，而失败案例使用扩展被动模式。您可能很难使用普通URL连接微调FTP连接。我强烈建议使用java客户端库，例如。您将在主页上找到一个FTP示例。

David，感谢您的回复。如果我理解正确，您所说的是URLConnection，或者sun.net.www.protocol.ftp（这是应用程序使用的，但这是一个更简单的测试）无法轻松设置为始终使用被动模式？请原谅任何错误的假设；我仍然在想为什么部署在X的应用程序会发出PASV，为什么Y的代码会发出EPSV。谢谢。是的，据我所知，没有简单的方法可以使用基本的URL连接来改变模式。请参阅此相关问题的回答：谢谢，使用apache的FTPClient并调用enterLocalPassiveMode现在有一个类似的测试正在运行。

(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> Connected, sending welcome message...
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> 220-FileZilla Server version 0.9.24 beta
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> 220 Connected to server FTP!
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> USER ftpUser
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> 331 Password required for ftpUser
(000217) 8/28/2012 11:25:11 AM - (not logged in) (ec2 Instance IP)> PASS *********
(000217) 8/28/2012 11:25:11 AM - ftpUser (ec2 Instance IP)> 230 Logged on
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> TYPE I
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 200 Type set to I
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> CWD DPS
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 250 CWD successful. "/DPS" is current directory.
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> CWD DP276
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 250 CWD successful. "/DPS/DP276" is current directory.
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> EPSV ALL
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 229 Entering Extended Passive Mode (|||1318|)
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> EPSV
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 229 Entering Extended Passive Mode (|||1319|)
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> EPRT |1|ec2 internal IP|37245|
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 200 Port command successful
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> RETR products.txt
(000217) 8/28/2012 11:25:12 AM - ftpUser (ec2 Instance IP)> 150 Opening data channel for file transfer.
(000217) 8/28/2012 11:25:23 AM - ftpUser (ec2 Instance IP)> 425 Can't open data connection.