Java FTPS 无法检索文件列表（FileZilla 客户端工作正常）

Question

Java FTPS 无法检索文件列表（FileZilla 客户端工作正常）

我使用带有 Java 8 的 Apache Commons Net (v3.5) 连接到远程 FTPS 站点（即在 Internet 上）。我可以在我的 Windows 10 机器上轻松连接 FileZilla 客户端，但我的 Java 程序无法完成相同的步骤。我在谷歌上搜索了高低，但找不到根本原因。以下是我已经确认的事情：

我确保 Java FTP 命令与 FileZilla 客户端的顺序完全相同。
我在 PC 上禁用了 Windows 防火墙和防病毒软件
我重新启用了 Windows 防火墙并启用了日志记录。使用 FileZilla 时，Windows 防火墙日志会在建立被动模式连接时列出 TCP 连接。我在 Java 程序中没有看到这样的条目。
我在我的 PC 上安装了 FileZilla 服务器。在我取消选中“使用 PROT P 时需要在数据连接上恢复 TLS 会话”后，java 程序运行。Java 例外是不同的，所以我不相信这是一个确凿的证据。
我成功地针对 test.rebex.com 服务器运行了相同的代码。

以下是代码，非常感谢您的任何想法：

import java.io.IOException;
import java.io.PrintWriter;
import org.apache.commons.net.PrintCommandListener;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;
import org.apache.commons.net.ftp.FTPSClient;

public class testProgram {

  public static void main(String[] args) {

    String ftpServer = "ftp.domain.com";
    String ftpUsername = "user@domain.com";
    String ftpPassword = "********";

    FTPSClient ftp = null;

    // CONNECT TO THE SERVER
    try {
        // I have tried "SSL" as the argument, but same result
        ftp = new FTPSClient(); 
        ftp.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));

        ftp.connect(ftpServer,21);

        int reply = ftp.getReplyCode();

        if (!FTPReply.isPositiveCompletion(reply)) {
            ftp.disconnect();
            System.err.println("---------->FTP server refused connection.\n");

        } 

    } catch (Exception e) {
        System.out.println(e.getMessage());
        e.printStackTrace();

    }

    // LOGIN INTO SERVER
    try {
        if (!ftp.login(ftpUsername, ftpPassword)) {
            ftp.logout();

        } else {

            ftp.sendCommand("OPTS UTF8 ON");            
            ftp.execPBSZ(0);            
            ftp.execPROT("P");
            ftp.pwd();
            ftp.setFileType(FTP.BINARY_FILE_TYPE);      
            ftp.enterLocalPassiveMode();

            /* The next command always fails.

               The FTP Server responds with "150 Accepted data connection" then:

                org.apache.commons.net.ftp.FTPConnectionClosedException: Connection closed without indication.
                at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:316)
                at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:292)
                at org.apache.commons.net.ftp.FTP.getReply(FTP.java:712)
                at org.apache.commons.net.ftp.FTPClient.completePendingCommand(FTPClient.java:1857)
                at org.apache.commons.net.ftp.FTPClient.listNames(FTPClient.java:2919)
                at org.apache.commons.net.ftp.FTPClient.listNames(FTPClient.java:2952)
                at myPackage.testProgram.main(testProgram.java:78)

                I have tried other commands, but it disconnects here...
             */

            FTPFile[] ftpFiles = ftp.listFiles();
            System.out.println("---------->Number of Files = " + ftpFiles.length);
            ftp.logout();

        }
    } catch (Exception e) {

        e.printStackTrace();
    } 

    //Ensure Disconnected at the end.
    if (ftp.isConnected()) {
        try {
            ftp.disconnect();
        } catch (IOException f) {
            // do nothing
        }

    }
  }
}

Run Code Online (Sandbox Code Playgroud)

这是我 PC 上的 FileZilla 客户端日志：

2016-09-06 09:09:50 4756 1 Status: Resolving address of ftp.domain.com
2016-09-06 09:09:51 4756 1 Status: Connecting to h1.h2.h3.h4:21...
2016-09-06 09:09:51 4756 1 Status: Connection established, waiting for welcome message...
2016-09-06 09:09:51 4756 1 Response: 220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
2016-09-06 09:09:51 4756 1 Response: 220-You are user number 2 of 50 allowed.
2016-09-06 09:09:51 4756 1 Response: 220-Local time is now 13:09. Server port: 21.
2016-09-06 09:09:51 4756 1 Response: 220-This is a private system - No anonymous login
2016-09-06 09:09:51 4756 1 Response: 220-IPv6 connections are also welcome on this server.
2016-09-06 09:09:51 4756 1 Response: 220 You will be disconnected after 15 minutes of inactivity.
2016-09-06 09:09:51 4756 1 Command: AUTH TLS
2016-09-06 09:09:51 4756 1 Response: 234 AUTH TLS OK.
2016-09-06 09:09:51 4756 1 Status: Initializing TLS...
2016-09-06 09:09:51 4756 1 Status: Verifying certificate...
2016-09-06 09:09:51 4756 1 Status: TLS connection established.
2016-09-06 09:09:51 4756 1 Command: USER user@domain.com
2016-09-06 09:09:51 4756 1 Response: 331 User user@domain.com OK. Password required
2016-09-06 09:09:51 4756 1 Command: PASS *************
2016-09-06 09:09:51 4756 1 Response: 230 OK. Current restricted directory is /
2016-09-06 09:09:51 4756 1 Command: SYST
2016-09-06 09:09:51 4756 1 Response: 215 UNIX Type: L8
2016-09-06 09:09:51 4756 1 Command: FEAT
2016-09-06 09:09:51 4756 1 Response: 211-Extensions supported:
2016-09-06 09:09:51 4756 1 Response:  EPRT
2016-09-06 09:09:51 4756 1 Response:  IDLE
2016-09-06 09:09:51 4756 1 Response:  MDTM
2016-09-06 09:09:51 4756 1 Response:  SIZE
2016-09-06 09:09:51 4756 1 Response:  MFMT
2016-09-06 09:09:51 4756 1 Response:  REST STREAM
2016-09-06 09:09:51 4756 1 Response:  MLST type*;size*;sizd*;modify*;UNIX.mode*;UNIX.uid*;UNIX.gid*;unique*;
2016-09-06 09:09:51 4756 1 Response:  MLSD
2016-09-06 09:09:51 4756 1 Response:  AUTH TLS
2016-09-06 09:09:51 4756 1 Response:  PBSZ
2016-09-06 09:09:51 4756 1 Response:  PROT
2016-09-06 09:09:51 4756 1 Response:  UTF8
2016-09-06 09:09:51 4756 1 Response:  TVFS
2016-09-06 09:09:51 4756 1 Response:  ESTA
2016-09-06 09:09:51 4756 1 Response:  PASV
2016-09-06 09:09:51 4756 1 Response:  EPSV
2016-09-06 09:09:51 4756 1 Response:  SPSV
2016-09-06 09:09:51 4756 1 Response:  ESTP
2016-09-06 09:09:51 4756 1 Response: 211 End.
2016-09-06 09:09:51 4756 1 Command: OPTS UTF8 ON
2016-09-06 09:09:51 4756 1 Response: 200 OK, UTF-8 enabled
2016-09-06 09:09:51 4756 1 Command: PBSZ 0
2016-09-06 09:09:51 4756 1 Response: 200 PBSZ=0
2016-09-06 09:09:51 4756 1 Command: PROT P
2016-09-06 09:09:52 4756 1 Response: 200 Data protection level set to "private"
2016-09-06 09:09:52 4756 1 Status: Logged in
2016-09-06 09:09:52 4756 1 Status: Retrieving directory listing...
2016-09-06 09:09:52 4756 1 Command: PWD
2016-09-06 09:09:52 4756 1 Response: 257 "/" is your current location
2016-09-06 09:09:52 4756 1 Command: TYPE I
2016-09-06 09:09:52 4756 1 Response: 200 TYPE is now 8-bit binary
2016-09-06 09:09:52 4756 1 Command: PASV
2016-09-06 09:09:52 4756 1 Response: 227 Entering Passive Mode (h1,h2,h3,h4,133,150)
2016-09-06 09:09:52 4756 1 Command: MLSD
2016-09-06 09:09:52 4756 1 Response: 150 Accepted data connection
2016-09-06 09:09:52 4756 1 Response: 226-Options: -a -l 
2016-09-06 09:09:52 4756 1 Response: 226 6 matches total

Run Code Online (Sandbox Code Playgroud)

使用 Mike 的建议，我打开了 TLS 调试。程序似乎再次通过 TLS 握手。输出很长，但在发出 list 命令后，我看到“*** ClientHello, TLSv1.2”以及与启动 FTP 连接的命令相同的命令。

差异似乎出现在最后：

%% Cached client session: [Session-2, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256]
main, received EOFException: ignored
main, called closeInternal(false)
main, SEND TLSv1.2 ALERT:  warning, description = close_notify
main, WRITE: TLSv1.2 Alert, length = 26
main, called closeSocket(false)
main, called close()
main, called closeInternal(true)
main, called close()
main, called closeInternal(true)
main, received EOFException: ignored
main, called closeInternal(false)
main, SEND TLSv1.2 ALERT:  warning, description = close_notify
main, WRITE: TLSv1.2 Alert, length = 26
main, called closeSocket(false)
org.apache.commons.net.ftp.FTPConnectionClosedException: Connection closed without indication.

Run Code Online (Sandbox Code Playgroud)

Answer 1

Try*_*arn 5

虽然这看起来像一个旧帖子，但我今天遇到了类似的问题并且无法（最初）找出解决方案。我可以通过 FileZilla 连接，但不能通过 FTPSClient 连接，运行后ftpClient.enterLocalPassiveMode()，我曾经得到425 cannot open data connection

我的解决方案是ftpClient.enterLocalPassiveMode()在登录之前更改但在连接到 FTPServer 之后它工作。通常我看到的所有代码示例都enterlocalpassivemode在发送/接收数据之前但在登录之后使用。有关对我有用的示例，请参见下面的代码。

FTPSClient ftpClient = new FTPSClient(false);
ftpClient.connect("remote.ftp.server", port);
ftpClient.enterLocalPassiveMode();// Run the passive mode command now  instead of after loggin in.
ftpClient.login("username", "password");
ftpClient.execPBSZ(0);
ftpClient.execPROT("P");
ftpClient.type(FTP.BINARY_FILE_TYPE);
//ftpClient.enterLocalPassiveMode(); Previously it was here.
FTPFile[] files = ftpClient.listDirectories("/");

Run Code Online (Sandbox Code Playgroud)

希望这可以帮助。另请注意，为了使答案简短，省略了所有其他代码和良好做法。

归档时间：	9 年，3 月前
查看次数：	6675 次
最近记录：	6 年，2 月前