networking - 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。在这里:

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)

代码如下:

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？

奇怪的是所有的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!

我还检查并发现我在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(protocol)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事件时断开连接。看起来是这种情况，因为 readFTPReply 尝试从控制连接读取并抛出 “读取超时”。

如何调试

您可以通过 Wireshark 在客户端转储流量或 tcpdump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:

1. 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事件并重置防火墙/路由器中的连接空闲计时器。我不确定 ftp4j 是否可以做到这一点。但是你可以切换到Apache FTPClient并使用 setControlKeepAliveTimeout .

2. 您可以尝试更新/更改防火墙/路由器。