ftp4j提示java.net.SocketException: Connection reset的解決
系統的自動更新FTP服務器，其他計算機連接都沒有問題，包括xp、server2008、win7、win8，簡體和繁體。
今天發現一台簡體win7無法自動更新，提示錯誤如下：
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.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:1
05)
at it.sauronsoftware.ftp4j.FTPCommunicationChannel.read(FTPCommunication
Channel.java:142)
at it.sauronsoftware.ftp4j.FTPCommunicationChannel.readFTPReply(FTPCommu
nicationChannel.java:185)
at it.sauronsoftware.ftp4j.FTPClient.openPassiveDataTransferChannel(FTPC
lient.java:3179)
at it.sauronsoftware.ftp4j.FTPClient.openDataTransferChannel(FTPClient.j
ava:3113)
at it.sauronsoftware.ftp4j.FTPClient.list(FTPClient.java:2019)
at it.sauronsoftware.ftp4j.FTPClient.list(FTPClient.java:2193)
at cn.stjauns.logan.updater.Updater.getRemotefiles(Updater.java:199)
at cn.stjauns.logan.updater.Updater.doUpdate(Updater.java:58)
at cn.stjauns.logan.updater.Starter.main(Starter.java:18)
關閉win7自帶防火牆，一切正常。
上百度查詢，無果。
上google查詢，答案見：http://stackoverflow.com/questions/10166337/ftp-error-while-downloading-uploading-with-ftp4j-library-in-java-application。
Apparently there is a bug on the Windows 7 firewall related to using FTP on IPv6 that would explain your problem. See bug report here.
Any one of the following workarounds should suffice to fix it:
Run the following as an administrator in a Windows console:
netsh advfirewall set global StatefulFtp disable
Run the JVM with the option: -Djava.net.preferIPv4Stack=true
打開win7防火牆，以管理員身份運行cmd，運行如下命令：
netsh advfirewall set global StatefulFtp disable
問題解決。