Package org.apache.commons.net.ftp

# Class FTP

java.lang.Object
org.apache.commons.net.SocketClient
org.apache.commons.net.ftp.FTP

Direct Known Subclasses:
  `FTPClient`

public class FTP extends SocketClient
FTP provides the basic the functionality necessary to implement your own FTP client. It extends org.apache.commons.net.SocketClient since extending TelnetClient was causing unwanted behavior (like connections that did not time out properly).

To derive the full benefits of the FTP class requires some knowledge of the FTP protocol defined in RFC 959. However, there is no reason why you should have to use the FTP class. The `FTPClient` class, derived from FTP, implements all the functionality required of an FTP client. The FTP class is made public to provide access to various FTP constants and to make it easier for adventurous programmers (or those with special needs) to interact with the FTP protocol and implement their own clients. A set of methods with names corresponding to the FTP command names are provided to facilitate this interaction.

You should keep in mind that the FTP server may choose to prematurely close a connection if the client has been idle for longer than a given time period (usually 900 seconds). The FTP class will detect a premature FTP server connection closing when it receives a `FTPReply.SERVICE_NOT_AVAILABLE` response to a command. When that occurs, the FTP class method encountering that reply will throw an `FTPConnectionClosedException`. `FTPConectionClosedException` is a subclass of `IOException` and therefore need not be caught separately, but if you are going to catch it separately, its catch block must appear before the more general `IOException` catch block. When you encounter an `FTPConnectionClosedException` , you must disconnect the connection with `disconnect()` to properly clean up the system resources used by FTP. Before disconnecting, you may check the last reply code and text with `getReplyCode`, `getReplyString`, and `getReplyStrings`. You may avoid server disconnections while the client is idle by periodically sending NOOP commands to the server.

Rather than list it separately for each method, we mention here that every method communicating with the server and throwing an IOException can also throw a `MalformedServerReplyException` , which is a subclass of IOException. A MalformedServerReplyException will be thrown when the reply received from the server deviates enough from the protocol specification that it cannot be interpreted in a useful manner despite attempts to be as lenient as possible.

See Also:
  - `FTPClient`
  - `FTPConnectionClosedException`
  - `MalformedServerReplyException`

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected ProtocolCommandSupport`
  `_commandSupport_`
  A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and the firing of ProtocolCommandEvents.
  `protected String`
  `_controlEncoding`
  The character encoding to be used by the FTP control connection.
  `protected BufferedReader`
  `_controlInput_`
  Wraps SocketClient.
  `protected BufferedWriter`
  `_controlOutput_`
  Wraps SocketClient.
  `protected boolean`
  `_newReplyString`
  Whether we've processed the last reply lines.
  `protected int`
  `_replyCode`
  The last FTP reply code.
  `protected ArrayList<String>`
  `_replyLines`
  The lines of text from the last FTP server response.
  `protected String`
  `_replyString`
  The text from the last FTP server response.
  `static final int`
  `ASCII_FILE_TYPE`
  A constant used to indicate the file(s) being transferred should be treated as ASCII.
  `static final int`
  `BINARY_FILE_TYPE`
  A constant used to indicate the file(s) being transferred should be treated as a binary image, i.e., no translations should be performed.
  `static final int`
  `BLOCK_TRANSFER_MODE`
  A constant used to indicate a file is to be transferred as a series of blocks.
  `static final int`
  `CARRIAGE_CONTROL_TEXT_FORMAT`
  A constant used to indicate a text file contains ASA vertical format control characters.
  `static final int`
  `COMPRESSED_TRANSFER_MODE`
  A constant used to indicate a file is to be transferred as FTP compressed data.
  `static final String`
  `DEFAULT_CONTROL_ENCODING`
  The default character encoding used for communicating over an FTP control connection.
  `static final int`
  `DEFAULT_DATA_PORT`
  The default FTP data port (20).
  `static final int`
  `DEFAULT_PORT`
  The default FTP control port (21).
  `static final int`
  `DEFLATE_TRANSFER_MODE`
  A constant used to indicate a file is to be transferred as FTP (un)compressing data in the "deflate" compression format.
  `static final int`
  `EBCDIC_FILE_TYPE`
  A constant used to indicate the file(s) being transferred should be treated as EBCDIC.
  `static final int`
  `FILE_STRUCTURE`
  A constant used to indicate a file is to be treated as a continuous sequence of bytes.
  `static final int`
  `LOCAL_FILE_TYPE`
  A constant used to indicate the file(s) being transferred should be treated as a local type.
  `static final int`
  `NON_PRINT_TEXT_FORMAT`
  A constant used for text files to indicate a non-print text format.
  `static final int`
  `PAGE_STRUCTURE`
  A constant used to indicate a file is to be treated as a set of independent indexed pages.
  `static final int`
  `RECORD_STRUCTURE`
  A constant used to indicate a file is to be treated as a sequence of records.
  `static final int`
  `REPLY_CODE_LEN`
  Length of the FTP reply code (3 alphanumerics)
  `static final int`
  `STREAM_TRANSFER_MODE`
  A constant used to indicate a file is to be transferred as a stream of bytes.
  `protected boolean`
  `strictMultilineParsing`
  This is used to signal whether a block of multiline responses beginning with xxx must be terminated by the same numeric code xxx See section 4.2 of RFC 959 for details.
  `static final int`
  `TELNET_TEXT_FORMAT`
  A constant used to indicate a text file contains format vertical format control characters.

  ### Fields inherited from class org.apache.commons.net.SocketClient

  `_defaultPort_, _hostname_, _input_, _output_, _serverSocketFactory_, _socket_, _socketFactory_, _timeout_, connectTimeout, NETASCII_EOL, remoteInetSocketAddress`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `FTP()`
  The default FTP constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `protected void`
  `__getReplyNoReport()`
  Gets the reply, but don't pass it to command listeners.
  `protected void`
  `__noop()`
  Send a noop and get the reply without reporting to the command listener.
  `protected void`
  `_connectAction_()`
  Initiates control connections and gets initial reply.
  `protected void`
  `_connectAction_(Reader socketIsReader)`
  Initiates control connections and gets initial reply.
  `int`
  `abor()`
  A convenience method to send the FTP ABOR command to the server, receive the reply, and return the reply code.
  `int`
  `acct(String account)`
  A convenience method to send the FTP ACCT command to the server, receive the reply, and return the reply code.
  `int`
  `allo(int bytes)`
  A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
  `int`
  `allo(int bytes, int recordSize)`
  A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
  `int`
  `allo(long bytes)`
  A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
  `int`
  `allo(long bytes, int recordSize)`
  A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
  `int`
  `appe(String path)`
  A convenience method to send the FTP APPE command to the server, receive the reply, and return the reply code.
  `int`
  `cdup()`
  A convenience method to send the FTP CDUP command to the server, receive the reply, and return the reply code.
  `int`
  `cwd(String directory)`
  A convenience method to send the FTP CWD command to the server, receive the reply, and return the reply code.
  `int`
  `dele(String path)`
  A convenience method to send the FTP DELE command to the server, receive the reply, and return the reply code.
  `void`
  `disconnect()`
  Closes the control connection to the FTP server and sets to null some internal data so that the memory may be reclaimed by the garbage collector.
  `int`
  `eprt(InetAddress host, int port)`
  A convenience method to send the FTP EPRT command to the server, receive the reply, and return the reply code.
  `int`
  `epsv()`
  A convenience method to send the FTP EPSV command to the server, receive the reply, and return the reply code.
  `int`
  `feat()`
  A convenience method to send the FTP FEAT command to the server, receive the reply, and return the reply code.
  `protected ProtocolCommandSupport`
  `getCommandSupport()`
  Gets protocol command support.
  `String`
  `getControlEncoding()`
  Gets the character encoding used to communicate over the control connection.
  `int`
  `getReply()`
  Gets a reply from the FTP server and returns the integer reply code.
  `int`
  `getReplyCode()`
  Gets the integer value of the reply code of the last FTP reply.
  `String`
  `getReplyString()`
  Gets the entire text of the last FTP server response exactly as it was received, including all end of line markers in NETASCII format.
  `String[]`
  `getReplyStrings()`
  Gets the lines of text from the last FTP server response as an array of strings, one entry per line.
  `int`
  `help()`
  A convenience method to send the FTP HELP command to the server, receive the reply, and return the reply code.
  `int`
  `help(String command)`
  A convenience method to send the FTP HELP command to the server, receive the reply, and return the reply code.
  `boolean`
  `isStrictMultilineParsing()`
  Tests whether strict multiline parsing is enabled, as per RFC 959, section 4.2.
  `boolean`
  `isStrictReplyParsing()`
  Tests whether strict non-multiline parsing is enabled, as per RFC 959, section 4.2.
  `int`
  `list()`
  A convenience method to send the FTP LIST command to the server, receive the reply, and return the reply code.
  `int`
  `list(String path)`
  A convenience method to send the FTP LIST command to the server, receive the reply, and return the reply code.
  `int`
  `mdtm(String file)`
  Sends the MDTM command for the given file.
  `int`
  `mfmt(String path, String timeval)`
  A convenience method to send the FTP MFMT command to the server, receive the reply, and return the reply code.
  `int`
  `mkd(String path)`
  A convenience method to send the FTP MKD command to the server, receive the reply, and return the reply code.
  `int`
  `mlsd()`
  A convenience method to send the FTP MLSD command to the server, receive the reply, and return the reply code.
  `int`
  `mlsd(String path)`
  A convenience method to send the FTP MLSD command to the server, receive the reply, and return the reply code.
  `int`
  `mlst()`
  A convenience method to send the FTP MLST command to the server, receive the reply, and return the reply code.
  `int`
  `mlst(String path)`
  A convenience method to send the FTP MLST command to the server, receive the reply, and return the reply code.
  `int`
  `mode(int mode)`
  A convenience method to send the FTP MODE command to the server, receive the reply, and return the reply code.
  `int`
  `nlst()`
  A convenience method to send the FTP NLST command to the server, receive the reply, and return the reply code.
  `int`
  `nlst(String path)`
  A convenience method to send the FTP NLST command to the server, receive the reply, and return the reply code.
  `int`
  `noop()`
  A convenience method to send the FTP NOOP command to the server, receive the reply, and return the reply code.
  `int`
  `opts(String... commandNameOptions)`
  A convenience method to send the FTP OPTS command to the server, receive the reply, and return the reply code.
  `int`
  `opts(String commandName, String commandOptions)`
  A convenience method to send the FTP OPTS command to the server, receive the reply, and return the reply code.
  `int`
  `pass(String password)`
  A convenience method to send the FTP PASS command to the server, receive the reply, and return the reply code.
  `int`
  `pasv()`
  A convenience method to send the FTP PASV command to the server, receive the reply, and return the reply code.
  `int`
  `port(InetAddress host, int port)`
  A convenience method to send the FTP PORT command to the server, receive the reply, and return the reply code.
  `int`
  `pwd()`
  A convenience method to send the FTP PWD command to the server, receive the reply, and return the reply code.
  `int`
  `quit()`
  A convenience method to send the FTP QUIT command to the server, receive the reply, and return the reply code.
  `int`
  `rein()`
  A convenience method to send the FTP REIN command to the server, receive the reply, and return the reply code.
  `int`
  `rest(String marker)`
  A convenience method to send the FTP REST command to the server, receive the reply, and return the reply code.
  `int`
  `retr(String path)`
  A convenience method to send the FTP RETR command to the server, receive the reply, and return the reply code.
  `int`
  `rmd(String path)`
  A convenience method to send the FTP RMD command to the server, receive the reply, and return the reply code.
  `int`
  `rnfr(String path)`
  A convenience method to send the FTP RNFR command to the server, receive the reply, and return the reply code.
  `int`
  `rnto(String path)`
  A convenience method to send the FTP RNTO command to the server, receive the reply, and return the reply code.
  `int`
  `sendCommand(int command)`
  Sends an FTP command with no arguments to the server, waits for a reply and returns the numerical response code.
  `int`
  `sendCommand(int command, String args)`
  Deprecated.
  (3.3) Use `sendCommand(FTPCmd, String)` instead
  `int`
  `sendCommand(String command)`
  Sends an FTP command with no arguments to the server, waits for a reply and returns the numerical response code.
  `int`
  `sendCommand(String command, String args)`
  Sends an FTP command to the server, waits for a reply and returns the numerical response code.
  `int`
  `sendCommand(FTPCmd command)`
  Sends an FTP command to the server, waits for a reply and returns the numerical response code.
  `int`
  `sendCommand(FTPCmd command, String args)`
  Sends an FTP command to the server, waits for a reply and returns the numerical response code.
  `void`
  `setControlEncoding(String encoding)`
  Sets the character encoding to be used by the FTP control connection.
  `void`
  `setControlEncoding(Charset charset)`
  Sets the character encoding to be used by the FTP control connection.
  `void`
  `setStrictMultilineParsing(boolean strictMultilineParsing)`
  Sets strict multiline parsing.
  `void`
  `setStrictReplyParsing(boolean strictReplyParsing)`
  Sets strict non-multiline parsing.
  `int`
  `site(String parameters)`
  A convenience method to send the FTP SITE command to the server, receive the reply, and return the reply code.
  `int`
  `size(String parameters)`
  A convenience method to send the FTP SIZE command to the server, receive the reply, and return the reply code.
  `int`
  `smnt(String dir)`
  A convenience method to send the FTP SMNT command to the server, receive the reply, and return the reply code.
  `int`
  `stat()`
  A convenience method to send the FTP STAT command to the server, receive the reply, and return the reply code.
  `int`
  `stat(String path)`
  A convenience method to send the FTP STAT command to the server, receive the reply, and return the reply code.
  `int`
  `stor(String path)`
  A convenience method to send the FTP STOR command to the server, receive the reply, and return the reply code.
  `int`
  `stou()`
  A convenience method to send the FTP STOU command to the server, receive the reply, and return the reply code.
  `int`
  `stou(String path)`
  A convenience method to send the FTP STOU command to the server, receive the reply, and return the reply code.
  `int`
  `stru(int structure)`
  A convenience method to send the FTP STRU command to the server, receive the reply, and return the reply code.
  `int`
  `syst()`
  A convenience method to send the FTP SYST command to the server, receive the reply, and return the reply code.
  `int`
  `type(int fileType)`
  A convenience method to send the FTP TYPE command to the server, receive the reply, and return the reply code.
  `int`
  `type(int fileType, int formatOrByteSize)`
  A convenience method to send the FTP TYPE command for text files to the server, receive the reply, and return the reply code.
  `int`
  `user(String user)`
  A convenience method to send the FTP USER command to the server, receive the reply, and return the reply code.

  ### Methods inherited from class org.apache.commons.net.SocketClient

  `addProtocolCommandListener, applySocketAttributes, checkOpenOutputStream, connect, connect, connect, connect, connect, connect, createCommandSupport, fireCommandSent, fireReplyReceived, getCharset, getCharsetName, getConnectTimeout, getDefaultPort, getDefaultTimeout, getHostAddress, getHostAddress, getKeepAlive, getLocalAddress, getLocalPort, getProxy, getReceiveBufferSize, getRemoteAddress, getRemoteInetSocketAddress, getRemotePort, getSendBufferSize, getServerSocketFactory, getSoLinger, getSoTimeout, getTcpNoDelay, isAvailable, isConnected, removeProtocolCommandListener, setCharset, setConnectTimeout, setDefaultPort, setDefaultTimeout, setKeepAlive, setProxy, setReceiveBufferSize, setSendBufferSize, setServerSocketFactory, setSocketFactory, setSoLinger, setSoTimeout, setTcpNoDelay, verifyRemote`

  ### Methods inherited from class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Field Details

  - ### DEFAULT_DATA_PORT

    public static final int DEFAULT_DATA_PORT
    The default FTP data port (20).
    See Also:
      - Constant Field Values

  - ### DEFAULT_PORT

    public static final int DEFAULT_PORT
    The default FTP control port (21).
    See Also:
      - Constant Field Values

  - ### ASCII_FILE_TYPE

    public static final int ASCII_FILE_TYPE
    A constant used to indicate the file(s) being transferred should be treated as ASCII. This is the default file type. All constants ending in `FILE_TYPE` are used to indicate file types.
    See Also:
      - Constant Field Values

  - ### EBCDIC_FILE_TYPE

    public static final int EBCDIC_FILE_TYPE
    A constant used to indicate the file(s) being transferred should be treated as EBCDIC. Note however that there are several EBCDIC formats. All constants ending in `FILE_TYPE` are used to indicate file types.
    See Also:
      - Constant Field Values

  - ### BINARY_FILE_TYPE

    public static final int BINARY_FILE_TYPE
    A constant used to indicate the file(s) being transferred should be treated as a binary image, i.e., no translations should be performed. All constants ending in `FILE_TYPE` are used to indicate file types.
    See Also:
      - Constant Field Values

  - ### LOCAL_FILE_TYPE

    public static final int LOCAL_FILE_TYPE
    A constant used to indicate the file(s) being transferred should be treated as a local type. All constants ending in `FILE_TYPE` are used to indicate file types.
    See Also:
      - Constant Field Values

  - ### NON_PRINT_TEXT_FORMAT

    public static final int NON_PRINT_TEXT_FORMAT
    A constant used for text files to indicate a non-print text format. This is the default format. All constants ending in `TEXT_FORMAT` are used to indicate text formatting for text transfers (both ASCII and EBCDIC).
    See Also:
      - Constant Field Values

  - ### TELNET_TEXT_FORMAT

    public static final int TELNET_TEXT_FORMAT
    A constant used to indicate a text file contains format vertical format control characters. All constants ending in `TEXT_FORMAT` are used to indicate text formatting for text transfers (both ASCII and EBCDIC).
    See Also:
      - Constant Field Values

  - ### CARRIAGE_CONTROL_TEXT_FORMAT

    public static final int CARRIAGE_CONTROL_TEXT_FORMAT
    A constant used to indicate a text file contains ASA vertical format control characters. All constants ending in `TEXT_FORMAT` are used to indicate text formatting for text transfers (both ASCII and EBCDIC).
    See Also:
      - Constant Field Values

  - ### FILE_STRUCTURE

    public static final int FILE_STRUCTURE
    A constant used to indicate a file is to be treated as a continuous sequence of bytes. This is the default structure. All constants ending in `_STRUCTURE` are used to indicate file structure for file transfers.
    See Also:
      - Constant Field Values

  - ### RECORD_STRUCTURE

    public static final int RECORD_STRUCTURE
    A constant used to indicate a file is to be treated as a sequence of records. All constants ending in `_STRUCTURE` are used to indicate file structure for file transfers.
    See Also:
      - Constant Field Values

  - ### PAGE_STRUCTURE

    public static final int PAGE_STRUCTURE
    A constant used to indicate a file is to be treated as a set of independent indexed pages. All constants ending in `_STRUCTURE` are used to indicate file structure for file transfers.
    See Also:
      - Constant Field Values

  - ### STREAM_TRANSFER_MODE

    public static final int STREAM_TRANSFER_MODE
    A constant used to indicate a file is to be transferred as a stream of bytes. This is the default transfer mode. All constants ending in `TRANSFER_MODE` are used to indicate file transfer modes.
    See Also:
      - Constant Field Values

  - ### BLOCK_TRANSFER_MODE

    public static final int BLOCK_TRANSFER_MODE
    A constant used to indicate a file is to be transferred as a series of blocks. All constants ending in `TRANSFER_MODE` are used to indicate file transfer modes.
    See Also:
      - Constant Field Values

  - ### COMPRESSED_TRANSFER_MODE

    public static final int COMPRESSED_TRANSFER_MODE
    A constant used to indicate a file is to be transferred as FTP compressed data. All constants ending in `TRANSFER_MODE` are used to indicate file transfer modes. Currently unused.
    See Also:
      - Constant Field Values

  - ### DEFLATE_TRANSFER_MODE

    public static final int DEFLATE_TRANSFER_MODE
    A constant used to indicate a file is to be transferred as FTP (un)compressing data in the "deflate" compression format. All constants ending in `TRANSFER_MODE` are used to indicate file transfer modes. See the Internet Draft Deflate transmission mode for FTP
    See Also:
      - Constant Field Values

  - ### DEFAULT_CONTROL_ENCODING

    public static final String DEFAULT_CONTROL_ENCODING
    The default character encoding used for communicating over an FTP control connection. The default encoding is an ASCII-compatible encoding. Some FTP servers expect other encodings. You can change the encoding used by an FTP instance with `setControlEncoding`.

  - ### REPLY_CODE_LEN

    public static final int REPLY_CODE_LEN
    Length of the FTP reply code (3 alphanumerics)
    See Also:
      - Constant Field Values

  - ### _replyCode

    protected int _replyCode
    The last FTP reply code.

  - ### _replyLines

    protected ArrayList<String> _replyLines
    The lines of text from the last FTP server response.

  - ### _newReplyString

    protected boolean _newReplyString
    Whether we've processed the last reply lines.

  - ### _replyString

    protected String _replyString
    The text from the last FTP server response.

  - ### _controlEncoding

    protected String _controlEncoding
    The character encoding to be used by the FTP control connection.

  - ### _commandSupport_

    protected ProtocolCommandSupport _commandSupport_
    A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and the firing of ProtocolCommandEvents.

  - ### strictMultilineParsing

    protected boolean strictMultilineParsing
    This is used to signal whether a block of multiline responses beginning with xxx must be terminated by the same numeric code xxx See section 4.2 of RFC 959 for details.

  - ### _controlInput_

    protected BufferedReader _controlInput_
    Wraps SocketClient._input_ to facilitate the reading of text from the FTP control connection. Do not access the control connection via SocketClient._input_. This member starts with a null value, is initialized in `_connectAction_()`, and set to null in `disconnect()`.

  - ### _controlOutput_

    protected BufferedWriter _controlOutput_
    Wraps SocketClient._output_ to facilitate the writing of text to the FTP control connection. Do not access the control connection via SocketClient._output_. This member starts with a null value, is initialized in `_connectAction_()`, and set to null in `disconnect()`.

- ## Constructor Details

  - ### FTP

    public FTP()
    The default FTP constructor. Sets the default port to `DEFAULT_PORT` and initializes internal data structures for saving FTP reply information.

- ## Method Details

  - ### __getReplyNoReport

    protected void __getReplyNoReport() throws IOException
    Gets the reply, but don't pass it to command listeners. Used for keep-alive processing only.
    Throws:
      `IOException` - on error
    Since:
      3.0

  - ### __noop

    protected void __noop() throws IOException
    Send a noop and get the reply without reporting to the command listener. Intended for use with keep-alive.
    Throws:
      `IOException` - on error
    Since:
      3.0

  - ### _connectAction_

    protected void _connectAction_() throws IOException
    Initiates control connections and gets initial reply. Initializes `_controlInput_` and `_controlOutput_`.
    Overrides:
      `_connectAction_` in class `SocketClient`
    Throws:
      `IOException` - (SocketException) if a problem occurs with the socket

  - ### _connectAction_

    protected void _connectAction_(Reader socketIsReader) throws IOException
    Initiates control connections and gets initial reply. Initializes `_controlInput_` and `_controlOutput_`.
    Parameters:
      `socketIsReader` - the reader to reuse (if non-null)
    Throws:
      `IOException` - on error
    Since:
      3.4

  - ### abor

    public int abor() throws IOException
    A convenience method to send the FTP ABOR command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### acct

    public int acct(String account) throws IOException
    A convenience method to send the FTP ACCT command to the server, receive the reply, and return the reply code.
    Parameters:
      `account` - The account name to access.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### allo

    public int allo(int bytes) throws IOException
    A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
    Parameters:
      `bytes` - The number of bytes to allocate.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### allo

    public int allo(int bytes, int recordSize) throws IOException
    A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
    Parameters:
      `bytes` - The number of bytes to allocate.
      `recordSize` - The size of a record.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### allo

    public int allo(long bytes) throws IOException
    A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
    Parameters:
      `bytes` - The number of bytes to allocate.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### allo

    public int allo(long bytes, int recordSize) throws IOException
    A convenience method to send the FTP ALLO command to the server, receive the reply, and return the reply code.
    Parameters:
      `bytes` - The number of bytes to allocate.
      `recordSize` - The size of a record.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### appe

    public int appe(String path) throws IOException
    A convenience method to send the FTP APPE command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - The path to use for the file when stored at the remote end of the transfer.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### cdup

    public int cdup() throws IOException
    A convenience method to send the FTP CDUP command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### cwd

    public int cwd(String directory) throws IOException
    A convenience method to send the FTP CWD command to the server, receive the reply, and return the reply code.
    Parameters:
      `directory` - The new working directory.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### dele

    public int dele(String path) throws IOException
    A convenience method to send the FTP DELE command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - The path to delete.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### disconnect

    public void disconnect() throws IOException
    Closes the control connection to the FTP server and sets to null some internal data so that the memory may be reclaimed by the garbage collector. The reply text and code information from the last command is voided so that the memory it used may be reclaimed. Also sets `_controlInput_` and `_controlOutput_` to null.
    Overrides:
      `disconnect` in class `SocketClient`
    Throws:
      `IOException` - If an error occurs while disconnecting.

  - ### eprt

    public int eprt(InetAddress host, int port) throws IOException
    A convenience method to send the FTP EPRT command to the server, receive the reply, and return the reply code.

    Examples:

    - EPRT |1|132.235.1.2|6275|
    - EPRT |2|1080::8:800:200C:417A|5282|
    Parameters:
      `host` - The host owning the port.
      `port` - The new port.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      2.2
    See Also:
      - "http://www.faqs.org/rfcs/rfc2428.html"

  - ### epsv

    public int epsv() throws IOException
    A convenience method to send the FTP EPSV command to the server, receive the reply, and return the reply code. Remember, it's up to you to interpret the reply string containing the host/port information.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      2.2

  - ### feat

    public int feat() throws IOException
    A convenience method to send the FTP FEAT command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received by the server
    Throws:
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      2.2

  - ### getCommandSupport

    protected ProtocolCommandSupport getCommandSupport()
    Gets protocol command support.
    Overrides:
      `getCommandSupport` in class `SocketClient`
    Returns:
      the CommandSupport instance, may be `null`

  - ### getControlEncoding

    public String getControlEncoding()
    Gets the character encoding used to communicate over the control connection.
    Returns:
      The character encoding used to communicate over the control connection.

  - ### getReply

    public int getReply() throws IOException
    Gets a reply from the FTP server and returns the integer reply code. After calling this method, the actual reply text can be accessed from either calling `getReplyString` or `getReplyStrings`. Only use this method if you are implementing your own FTP client or if you need to fetch a secondary response from the FTP server.
    Returns:
      The integer value of the reply code of the fetched FTP reply.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while receiving the server reply.

  - ### getReplyCode

    public int getReplyCode()
    Gets the integer value of the reply code of the last FTP reply. You will usually only use this method after you connect to the FTP server to check that the connection was successful since `connect` is of type void.
    Returns:
      The integer value of the reply code of the last FTP reply.

  - ### getReplyString

    public String getReplyString()
    Gets the entire text of the last FTP server response exactly as it was received, including all end of line markers in NETASCII format.
    Returns:
      The entire text from the last FTP response as a String.

  - ### getReplyStrings

    public String[] getReplyStrings()
    Gets the lines of text from the last FTP server response as an array of strings, one entry per line. The end of line markers of each are stripped from each line.
    Returns:
      The lines of text from the last FTP response as an array.

  - ### help

    public int help() throws IOException
    A convenience method to send the FTP HELP command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### help

    public int help(String command) throws IOException
    A convenience method to send the FTP HELP command to the server, receive the reply, and return the reply code.
    Parameters:
      `command` - The command name on which to request help.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### isStrictMultilineParsing

    public boolean isStrictMultilineParsing()
    Tests whether strict multiline parsing is enabled, as per RFC 959, section 4.2.
    Returns:
      True if strict, false if lenient
    Since:
      2.0

  - ### isStrictReplyParsing

    public boolean isStrictReplyParsing()
    Tests whether strict non-multiline parsing is enabled, as per RFC 959, section 4.2.

    The default is true, which requires the 3-digit code be followed by space and some text. If false, only the 3-digit code is required (as was the case for versions up to 3.5).

    Returns:
      True if strict (default), false if additional checks are not made
    Since:
      3.6

  - ### list

    public int list() throws IOException
    A convenience method to send the FTP LIST command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### list

    public int list(String path) throws IOException
    A convenience method to send the FTP LIST command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - The path to list, may be `null` in which case the command is sent with no parameters
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### mdtm

    public int mdtm(String file) throws IOException
    Sends the MDTM command for the given file.
    Parameters:
      `file` - name of file
    Returns:
      the status
    Throws:
      `IOException` - on error
    Since:
      2.0

  - ### mfmt

    public int mfmt(String path, String timeval) throws IOException
    A convenience method to send the FTP MFMT command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - The path for which mtime is to be changed
      `timeval` - Timestamp in `yyyyMMDDhhmmss` format
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      2.2
    See Also:
      - https://tools.ietf.org/html/draft-somers-ftp-mfxx-04

  - ### mkd

    public int mkd(String path) throws IOException
    A convenience method to send the FTP MKD command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - The path of the new directory to create.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### mlsd

    public int mlsd() throws IOException
    A convenience method to send the FTP MLSD command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.0

  - ### mlsd

    public int mlsd(String path) throws IOException
    A convenience method to send the FTP MLSD command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - the path to report on
    Returns:
      The reply code received from the server, may be `null` in which case the command is sent with no parameters
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.0

  - ### mlst

    public int mlst() throws IOException
    A convenience method to send the FTP MLST command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.0

  - ### mlst

    public int mlst(String path) throws IOException
    A convenience method to send the FTP MLST command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - the path to report on
    Returns:
      The reply code received from the server, may be `null` in which case the command is sent with no parameters
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.0

  - ### mode

    public int mode(int mode) throws IOException
    A convenience method to send the FTP MODE command to the server, receive the reply, and return the reply code.
    Parameters:
      `mode` - The transfer mode to use (one of the `TRANSFER_MODE` constants).
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### nlst

    public int nlst() throws IOException
    A convenience method to send the FTP NLST command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### nlst

    public int nlst(String path) throws IOException
    A convenience method to send the FTP NLST command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - The path to list, may be `null` in which case the command is sent with no parameters
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### noop

    public int noop() throws IOException
    A convenience method to send the FTP NOOP command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### opts

    public int opts(String... commandNameOptions) throws IOException
    A convenience method to send the FTP OPTS command to the server, receive the reply, and return the reply code.

    FTP request Syntax:

         opts             = opts-cmd SP command-name [ SP command-options ] CRLF
         opts-cmd         = "opts"
         command-name     = <any FTP command which allows option setting>
         command-options  = <format specified by individual FTP command>

    Parameters:
      `commandNameOptions` - The OPTS command name and options.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.12.0

  - ### opts

    public int opts(String commandName, String commandOptions) throws IOException
    A convenience method to send the FTP OPTS command to the server, receive the reply, and return the reply code.

    FTP request Syntax:

         opts             = opts-cmd SP command-name [ SP command-options ] CRLF
         opts-cmd         = "opts"
         command-name     = <any FTP command which allows option setting>
         command-options  = <format specified by individual FTP command>

    Parameters:
      `commandName` - The OPTS command name.
      `commandOptions` - The OPTS command options.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.12.0

  - ### pass

    public int pass(String password) throws IOException
    A convenience method to send the FTP PASS command to the server, receive the reply, and return the reply code.
    Parameters:
      `password` - The plain text password of the user being logged into.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### pasv

    public int pasv() throws IOException
    A convenience method to send the FTP PASV command to the server, receive the reply, and return the reply code. Remember, it's up to you to interpret the reply string containing the host/port information.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### port

    public int port(InetAddress host, int port) throws IOException
    A convenience method to send the FTP PORT command to the server, receive the reply, and return the reply code.
    Parameters:
      `host` - The host owning the port.
      `port` - The new port.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### pwd

    public int pwd() throws IOException
    A convenience method to send the FTP PWD command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### quit

    public int quit() throws IOException
    A convenience method to send the FTP QUIT command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### rein

    public int rein() throws IOException
    A convenience method to send the FTP REIN command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### rest

    public int rest(String marker) throws IOException
    A convenience method to send the FTP REST command to the server, receive the reply, and return the reply code.
    Parameters:
      `marker` - The marker at which to restart a transfer.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### retr

    public int retr(String path) throws IOException
    A convenience method to send the FTP RETR command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - The path of the file to retrieve.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### rmd

    public int rmd(String path) throws IOException
    A convenience method to send the FTP RMD command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - The path of the directory to remove.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### rnfr

    public int rnfr(String path) throws IOException
    A convenience method to send the FTP RNFR command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - The path to rename from.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### rnto

    public int rnto(String path) throws IOException
    A convenience method to send the FTP RNTO command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - The path to rename to
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### sendCommand

    public int sendCommand(FTPCmd command) throws IOException
    Sends an FTP command to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling `getReplyString` or `getReplyStrings`.
    Parameters:
      `command` - The FTPCmd enum corresponding to the FTP command to send.
    Returns:
      The integer value of the FTP reply code returned by the server in response to the command.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.3

  - ### sendCommand

    public int sendCommand(FTPCmd command, String args) throws IOException
    Sends an FTP command to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling `getReplyString` or `getReplyStrings`.
    Parameters:
      `command` - The FTPCmd enum corresponding to the FTP command to send.
      `args` - The arguments to the FTP command. If this parameter is set to null, then the command is sent with no argument.
    Returns:
      The integer value of the FTP reply code returned by the server in response to the command.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.3

  - ### sendCommand

    public int sendCommand(int command) throws IOException
    Sends an FTP command with no arguments to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling `getReplyString` or `getReplyStrings`.
    Parameters:
      `command` - The FTPCommand constant corresponding to the FTP command to send.
    Returns:
      The integer value of the FTP reply code returned by the server in response to the command.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### sendCommand

    @Deprecated public int sendCommand(int command, String args) throws IOException
    Deprecated.
    (3.3) Use `sendCommand(FTPCmd, String)` instead
    Sends an FTP command to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling `getReplyString` or `getReplyStrings`.
    Parameters:
      `command` - The FTPCommand constant corresponding to the FTP command to send.
      `args` - The arguments to the FTP command. If this parameter is set to null, then the command is sent with no argument.
    Returns:
      The integer value of the FTP reply code returned by the server in response to the command.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### sendCommand

    public int sendCommand(String command) throws IOException
    Sends an FTP command with no arguments to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling `getReplyString` or `getReplyStrings`.
    Parameters:
      `command` - The text representation of the FTP command to send.
    Returns:
      The integer value of the FTP reply code returned by the server in response to the command.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### sendCommand

    public int sendCommand(String command, String args) throws IOException
    Sends an FTP command to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling `getReplyString` or `getReplyStrings`.
    Parameters:
      `command` - The text representation of the FTP command to send.
      `args` - The arguments to the FTP command. If this parameter is set to null, then the command is sent with no argument.
    Returns:
      The integer value of the FTP reply code returned by the server in response to the command.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### setControlEncoding

    public void setControlEncoding(Charset charset)
    Sets the character encoding to be used by the FTP control connection. Some FTP servers require that commands be issued in a non-ASCII encoding like UTF-8 so that file names with multi-byte character representations (e.g, Big 8) can be specified.

    Please note that this has to be set before the connection is established.

    Parameters:
      `charset` - The new character encoding for the control connection.
    Since:
      3.12.0

  - ### setControlEncoding

    public void setControlEncoding(String encoding)
    Sets the character encoding to be used by the FTP control connection. Some FTP servers require that commands be issued in a non-ASCII encoding like UTF-8 so that file names with multi-byte character representations (e.g, Big 8) can be specified.

    Please note that this has to be set before the connection is established.

    Parameters:
      `encoding` - The new character encoding for the control connection.

  - ### setStrictMultilineParsing

    public void setStrictMultilineParsing(boolean strictMultilineParsing)
    Sets strict multiline parsing.
    Parameters:
      `strictMultilineParsing` - the setting
    Since:
      2.0

  - ### setStrictReplyParsing

    public void setStrictReplyParsing(boolean strictReplyParsing)
    Sets strict non-multiline parsing.

    If true, it requires the 3-digit code be followed by space and some text. If false, only the 3-digit code is required (as was the case for versions up to 3.5).

    This should not be required by a well-behaved FTP server

    Parameters:
      `strictReplyParsing` - the setting
    Since:
      3.6

  - ### site

    public int site(String parameters) throws IOException
    A convenience method to send the FTP SITE command to the server, receive the reply, and return the reply code.
    Parameters:
      `parameters` - The site parameters to send.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### size

    public int size(String parameters) throws IOException
    A convenience method to send the FTP SIZE command to the server, receive the reply, and return the reply code.
    Parameters:
      `parameters` - The site parameters to send.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.
    Since:
      3.7

  - ### smnt

    public int smnt(String dir) throws IOException
    A convenience method to send the FTP SMNT command to the server, receive the reply, and return the reply code.
    Parameters:
      `dir` - The directory name.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### stat

    public int stat() throws IOException
    A convenience method to send the FTP STAT command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### stat

    public int stat(String path) throws IOException
    A convenience method to send the FTP STAT command to the server, receive the reply, and return the reply code.
    Parameters:
      `path` - A path to list.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### stor

    public int stor(String path) throws IOException
    A convenience method to send the FTP STOR command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - The path to use for the file when stored at the remote end of the transfer.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### stou

    public int stou() throws IOException
    A convenience method to send the FTP STOU command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### stou

    public int stou(String path) throws IOException
    A convenience method to send the FTP STOU command to the server, receive the reply, and return the reply code. Remember, it is up to you to manage the data connection. If you don't need this low level of access, use `FTPClient` , which will handle all low level details for you.
    Parameters:
      `path` - The base path to use for the file when stored at the remote end of the transfer. Some FTP servers require this.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### stru

    public int stru(int structure) throws IOException
    A convenience method to send the FTP STRU command to the server, receive the reply, and return the reply code.
    Parameters:
      `structure` - The structure of the file (one of the `_STRUCTURE` constants).
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### syst

    public int syst() throws IOException
    A convenience method to send the FTP SYST command to the server, receive the reply, and return the reply code.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### type

    public int type(int fileType) throws IOException
    A convenience method to send the FTP TYPE command to the server, receive the reply, and return the reply code.
    Parameters:
      `fileType` - The type of the file (one of the `FILE_TYPE` constants).
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### type

    public int type(int fileType, int formatOrByteSize) throws IOException
    A convenience method to send the FTP TYPE command for text files to the server, receive the reply, and return the reply code.
    Parameters:
      `fileType` - The type of the file (one of the `FILE_TYPE` constants).
      `formatOrByteSize` - The format of the file (one of the `_FORMAT` constants). In the case of `LOCAL_FILE_TYPE`, the byte size.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.

  - ### user

    public int user(String user) throws IOException
    A convenience method to send the FTP USER command to the server, receive the reply, and return the reply code.
    Parameters:
      `user` - The user to login under.
    Returns:
      The reply code received from the server.
    Throws:
      `FTPConnectionClosedException` - If the FTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send FTP reply code 421. This exception may be caught either as an IOException or independently as itself.
      `IOException` - If an I/O error occurs while either sending the command or receiving the server reply.