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Java FTPS fails to retrieve file list (FileZilla Client works fine)

由 时光怂恿深爱的人放手 提交于 2019-12-01 01:49:29

Although this looks like an old post, I was faced with a similar problem today and could not figure out (initially) the solution. I could connect via FileZilla but not with FTPSClient and after running ftpClient.enterLocalPassiveMode(), I used to get 425 cannot open data connection

My solution was to change the ftpClient.enterLocalPassiveMode() before logging in but after connecting to the FTPServer and it worked. Usually all code examples I saw uses the enterlocalpassivemode before sending/receiving the data but after login. See below code for an example which worked for me.

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("/");

Hope this helps. Please also note that all other code and good practices are omitted to keep the answer short.

This example works with TLS security.
Server - VSFTPD in Centos

----------VSFTPD.conf TLS addition ---------
....

rsa_cert_file=path to .pem/.p12 file
rsa_private_key_file=path to .pem/.p12 file
ssl_enable=YES
allow_anon_ssl=NO
force_local_data_ssl=YES
force_local_logins_ssl=YES
ssl_enable=YES
allow_anon_ssl=NO
ssl_tlsv1=YES
ssl_sslv2=YES
ssl_sslv3=YES
require_ssl_reuse=NO

--------------------------------------------
The apache 3.5 commons net Java code below
----------------------------------------

public static final void main(String[] args) throws Exception {
    // System.setProperty("javax.net.debug", "ssl");
    ftps_ = createFtpClient();
    ftpsClient_.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));
    ftps_.connect("<FTPS SERVER Address>");
    boolean login = ftps_.login("user", "password");
    ftps_.type(FTP.ASCII_FILE_TYPE);
    ftps_.execPROT("P");
    System.out.println("Login status -- " + login);
    System.out.println("----------Listing files---------");
    String dirName = "<dirName>";
    listFiles(dirName);
    ftps_.disconnect();
}

/**
 * Create the FTPS client.
 */
private static FTPSClient createFtpClient() throws Exception {
    String type = "PKCS12";
    String file = "<path to .p12 cert file>";
    String password = "ftpserver";

    KeyStore keyStore = KeyStore.getInstance(type);
    FileInputStream keyStoreFileInputStream = new FileInputStream(new File(file));
    try {
        keyStore.load(keyStoreFileInputStream, password.toCharArray());
    } catch (Exception e) {
        e.printStackTrace();
        System.exit(1);
    }
    KeyManagerFactory keyMgrFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
    keyMgrFactory.init(keyStore, password.toCharArray());
    KeyStore trustStore = KeyStore.getInstance(type);
    FileInputStream trustStoreFileInputStream = new FileInputStream(new File(file));
    try {
        trustStore.load(trustStoreFileInputStream, password.toCharArray());
    } catch (Exception e) {
        e.printStackTrace();
        System.exit(1);
    }
    TrustManagerFactory trustMgrFactory = TrustManagerFactory
            .getInstance(TrustManagerFactory.getDefaultAlgorithm());
    trustMgrFactory.init(trustStore);
    SSLContext sslContext = SSLContext.getInstance("TLSv1");
    sslContext.init(keyMgrFactory.getKeyManagers(), trustMgrFactory.getTrustManagers(), new SecureRandom());
    FTPSClient client = new FTPSClient(sslContext);
    return client;
}

private static void listFiles(String dirName) throws IOException {
    try {
        FTPFile[] list = ftps_.listFiles(dirName);
        for (int i = 0; i < list.length; i++) {
            System.out.println(list[i].getName());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
标签
java
ssl
ftp
apache-commons-net
ftps
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