ftp4j：client.login返回無法識別的SSL消息，純文本連接？

Question

這是我的代碼

try{
    TrustManager[] trustManager = new TrustManager[] { new X509TrustManager() {
        public X509Certificate[] getAcceptedIssuers() { return null; }
        public void checkClientTrusted(X509Certificate[] certs, String authType) {}
        public void checkServerTrusted(X509Certificate[] certs, String authType) {}
    } };

    SSLContext sslContext = null;

    sslContext = SSLContext.getInstance("TLS");
    sslContext.init(null, trustManager, new SecureRandom());
    SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();
    FTPClient client = new FTPClient();

    client.setSSLSocketFactory(sslSocketFactory);
    client.setSecurity(FTPClient.SECURITY_FTPES);

    client.connect("xxx.xxx.xxx", 21);
    System.out.println("Connected (" + client.isConnected() + ") to host " + client.getHost() + ":" + client.getPort());
    client.login("xxxxx", "xxxxx");            
}catch (Exception e) {
    e.printStackTrace();
}

運行時返回

Connected (true) to host xxx.xxx.xxx:21

然后在client.login（“ xxxxx”，“ xxxxx”）;上斷開 有例外

javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?

知道為什么會這樣嗎？

Java版本是1.4.2，ftp4j版本是1.7.2

Answer 1

消息很清楚。 您正在與純文本對等方通信。 該主機的端口21上確實有一個FTPS服務器嗎？

Answer 2

請確保使用正確的安全設置，例如FTPClient.SECURITY_FTPS或FTPClient.SECURITY_FTPES

FTPS（基於隱式TLS / SSL的FTP）和FTPES（基於顯式TLS / SSL的FTP）