上传文件后ftp4j读取超时

Question

我在从特定工作站上传文件（使用 ftp4j 库）期间收到奇怪的异常。

文件上传 (100%) 后，我收到读取超时异常。这是：

2015-03-20 18:14:43 INFO  TranferFileFtp4j:760 - FTP Server supports resume. Trying to upload file
2015-03-20 18:14:43 INFO  Ftp4jListener:38 - TRANSFER-STATUS: File transfer started
2015-03-20 18:14:43 INFO  Ftp4jListener:47 - File: 152818571.zip | Bytes transfered 65536 Percentage: 0.024173772%
...
2015-03-20 18:20:08 INFO  Ftp4jListener:47 - File: 153740599.zip | Bytes transfered 244383744 Percentage: 99.89077%
2015-03-20 18:20:08 INFO  Ftp4jListener:47 - File: 153740599.zip | Bytes transfered 244449280 Percentage: 99.91756%
2015-03-20 18:20:08 INFO  Ftp4jListener:47 - File: 153740599.zip | Bytes transfered 244514816 Percentage: 99.94434%
2015-03-20 18:20:08 INFO  Ftp4jListener:47 - File: 153740599.zip | Bytes transfered 244580352 Percentage: 99.97113%
2015-03-20 18:20:08 INFO  Ftp4jListener:47 - File: 153740599.zip | Bytes transfered 244645888 Percentage: 99.99792%
2015-03-20 18:20:08 INFO  Ftp4jListener:47 - File: 153740599.zip | Bytes transfered 244650979 Percentage: 100.0%
2015-03-20 18:20:18 INFO  TranferFileFtp4j:803 - Failed to send File! IOException other exceptionRead timed out - null
java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(Unknown Source)
    at java.net.SocketInputStream.read(Unknown Source)
    at sun.security.ssl.InputRecord.readFully(Unknown Source)
    at sun.security.ssl.InputRecord.read(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readDataRecord(Unknown Source)
    at sun.security.ssl.AppInputStream.read(Unknown Source)
    at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
    at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
    at sun.nio.cs.StreamDecoder.read(Unknown Source)
    at sun.nio.cs.StreamDecoder.read0(Unknown Source)
    at sun.nio.cs.StreamDecoder.read(Unknown Source)
    at java.io.InputStreamReader.read(Unknown Source)
    at it.sauronsoftware.ftp4j.NVTASCIIReader.readLine(NVTASCIIReader.java:105)
    at it.sauronsoftware.ftp4j.FTPCommunicationChannel.read(FTPCommunicationChannel.java:142)
    at it.sauronsoftware.ftp4j.FTPCommunicationChannel.readFTPReply(FTPCommunicationChannel.java:187)
    at it.sauronsoftware.ftp4j.FTPClient.upload(FTPClient.java:2797)
    at it.sauronsoftware.ftp4j.FTPClient.upload(FTPClient.java:2586)
    at com.npap.network.TranferFileFtp4j.uploadFileFtps5(TranferFileFtp4j.java:765)
    at com.npap.utils.ProcessDicomFiles.sendZippFiles(ProcessDicomFiles.java:215)
    at com.npap.scheduler.MainJob.execute(MainJob.java:97)
    at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
    at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
    java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(Unknown Source)
    at java.net.SocketInputStream.read(Unknown Source)
    at sun.security.ssl.InputRecord.readFully(Unknown Source)
    at sun.security.ssl.InputRecord.read(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readDataRecord(Unknown Source)
    at sun.security.ssl.AppInputStream.read(Unknown Source)
    at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
    at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
    at sun.nio.cs.StreamDecoder.read(Unknown Source)
    at sun.nio.cs.StreamDecoder.read0(Unknown Source)
    at sun.nio.cs.StreamDecoder.read(Unknown Source)
    at java.io.InputStreamReader.read(Unknown Source)
    at it.sauronsoftware.ftp4j.NVTASCIIReader.readLine(NVTASCIIReader.java:105)
    at it.sauronsoftware.ftp4j.FTPCommunicationChannel.read(FTPCommunicationChannel.java:142)
    at it.sauronsoftware.ftp4j.FTPCommunicationChannel.readFTPReply(FTPCommunicationChannel.java:187)
    at it.sauronsoftware.ftp4j.FTPClient.disconnect(FTPClient.java:1133)
    at com.npap.network.TranferFileFtp4j.uploadFileFtps5(TranferFileFtp4j.java:826)
    at com.npap.utils.ProcessDicomFiles.sendZippFiles(ProcessDicomFiles.java:215)
    at com.npap.scheduler.MainJob.execute(MainJob.java:97)
    at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
    at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)

这是代码：

ftpClient = Ftp4jUtility.ftpsConnect(SERVER_MACHINE, PORT, SERVER_USERNAME, SERVER_PASSWORD, stdId);
ftpClient.changeDirectory(config.getFtpRemoteFolderUploads());

 if(ftpClient.isResumeSupported()) {
     ftpClient.upload(localFile, writtenBytes, new Ftp4jListener(localFile.length(), localFile.getName()));
 } else {
     ftpClient.upload(localFile, new Ftp4jListener(localFile.length(), localFile.getName()));
 }

completed = true;

} catch (FTPAbortedException e) {
    ....
    break;
} catch (FTPDataTransferException ex1) {
    studyDetailsDAO.updateStudyIsInProgress(stdId, false);
    ex1.printStackTrace();
    ....
} catch (FTPException ex1) {
   ex1.printStackTrace();
   ....
} catch (FTPIllegalReplyException ex1) {
   ex1.printStackTrace();
   ...
} catch (IOException ex1) {
   log.info("Failed to send File! IOException " + ex1.getMessage());
   ex1.printStackTrace();
} catch (IllegalStateException ex1) {
   ...
} finally {
   if(ftpClient!=null && ftpClient.isConnected()) {
       try {
           ftpClient.disconnect(true); 
       } catch (Throwable t) {
           t.printStackTrace();
       }
   }
}

我收到此异常：IOException - 读取超时！任何想法是什么造成的？或者如何进行调试？

奇怪的是所有 ftp 操作都正常！我也能够开始并实际上传文件，但是在 ftpClient.upload 操作结束时我收到了这个超时！

我也检查过并发现我从特定工作站遇到了这个特殊问题。我什至尝试使用 filezilla 上传文件，但我收到了类似的异常（读取超时）。所以我猜这是网络或防火墙问题...有什么想法吗？

有什么想法吗？

Answer 1

可能的问题

FTP 协议在客户端和服务器之间使用单独的控制和数据 TCP 连接。在文件传输期间，数据连接繁忙，但控制连接空闲。根据您的日志，传输需要 15 分钟。这意味着控制连接在那段时间是空闲的。某些防火墙或网络路由器可以在一段时间内没有任何 activity 断开连接。看起来是这样，因为 readFTPReply 尝试从控制连接读取并抛出 "Read timed out".

如何调试

你可以通过Wireshark or tcpdump在客户端进行流量转储，并尝试找出控制连接断开的原因。

如何修复

我可以看到两种解决问题的方法：

您可以通过控制连接 ping 服务器发送 NOOP 命令以在传输期间进行一些 activity 并在 firewalls/routers 中重置连接的空闲计时器。我不确定 ftp4j 是否可以做到这一点。但是你可以切换到 Apache FTPClient and use setControlKeepAliveTimeout.
你可以试试update/change firewalls/routers.

上传文件后ftp4j读取超时

ftp4j read timed out after upload file

ftp

networking

network-programming

ftps

ftp4j