无法从java应用程序连接到远程FileZilla ftp服务器

我有一个运行在windows机器上的远程FileZilla ftp服务器。ftp服务器需要通过TLS显式ftp。协议是FTP而不是SFTP。我无法更改此服务器的设置。我可以使用filezilla gui客户端连接到此服务器

现在，我需要使用org.apache.commons.net通过java应用程序连接到FileZilla服务器：

  private void connect(String host, String user, String password) {
    try {
      FTPSClient ftpClient = new FTPSClient(false);
      ftpClient.connect(host);
      int reply = ftpClient.getReplyCode();
      if (FTPReply.isPositiveCompletion(reply)) {
        // Login
        if (ftpClient.login(user, password)) {

          // Set protection buffer size
          ftpClient.execPBSZ(0);
          // Set data channel protection to private
          ftpClient.execPROT("P");
          // Enter local passive mode
          ftpClient.enterLocalPassiveMode();
          ftpClient.logout();
        } else {
          System.out.println("FTP login failed");
        }
        // Disconnect
        ftpClient.disconnect();
      } else {
        System.out.println("FTP connect to host failed");
      }
    } catch (IOException ioe) {
      ioe.printStackTrace();
      System.out.println("FTP client received network error");
    }
  }

但当我运行上述代码时，我得到：

javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateExpiredException: NotAfter: Thu Aug 30 13:31:23 CEST 2012
    at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:174)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1764)

说到：

  ftpClient.connect(host);

关于如何使用org.apache.commons.net从java代码连接到Filezilla服务器，有什么想法吗

编辑： 我现在已尝试更改为FTPClient（即使这允许我设置显式TLS）：

---

但是login=false，我得到：“FTP登录失败”。如果我调试apache源代码，我会看到回复代码是：530=“未登录”：

创建SSLContext解决了问题：

  SSLContext sslContext = SSLContext.getInstance("TLS");
  TrustManager tm = new X509TrustManager() {
    public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
    }

    public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
    }

    public X509Certificate[] getAcceptedIssuers() {
      return null;
    }
  };
  sslContext.init(null, new TrustManager[] { tm }, null);
  FTPSClient ftpsClient = new FTPSClient(sslContext);

---

看起来像是安全问题。您是否尝试了FTPClient:而不是FTPSClient？您确定FTP服务器的证书有效吗？

  SSLContext sslContext = SSLContext.getInstance("TLS");
  TrustManager tm = new X509TrustManager() {
    public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
    }

    public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
    }

    public X509Certificate[] getAcceptedIssuers() {
      return null;
    }
  };
  sslContext.init(null, new TrustManager[] { tm }, null);
  FTPSClient ftpsClient = new FTPSClient(sslContext);