Class RExecClient
- Direct Known Subclasses:
- RCommandClient
 As with virtually all the client classes in org.apache.commons.net, this class derives from SocketClient, inheriting its connection methods. The way to
 use RExecClient is to first connect to the server, call the rexec() method, and then fetch the connection's input, output, and optionally
 error streams. Interaction with the remote command is controlled entirely through the I/O streams. Once you have finished processing the streams, you should
 invoke disconnect() to clean up properly.
 
 By default, the standard output and standard error streams of the remote process are transmitted over the same connection, readable from the input stream
 returned by getInputStream(). However, it is possible to tell the rexecd daemon to return the standard error stream over a separate
 connection, readable from the input stream returned by getErrorStream(). You can specify that a separate connection should be created
 for standard error by setting the boolean separateErrorStream parameter of rexec() to true. The standard input
 of the remote process can be written to through the output stream returned by getOutputSream().
- See Also:
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Field SummaryFieldsModifier and TypeFieldDescriptionprotected InputStreamIf a separate error stream is requested,_errorStream_will point to an InputStream from which the standard error of the remote process can be read (after a call to rexec()).static final intThe default rexec port.protected static final charFields inherited from class org.apache.commons.net.SocketClient_defaultPort_, _hostname_, _input_, _output_, _serverSocketFactory_, _socket_, _socketFactory_, _timeout_, connectTimeout, NETASCII_EOL, remoteInetSocketAddress
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidDisconnects from the server, closing all associated open sockets and streams.Returns the InputStream from which the standard error of the remote process can be read if a separate error stream is requested from the server.Returns the InputStream from which the standard output of the remote process can be read.Returns the OutputStream through which the standard input of the remote process can be written.final booleanReturn whether or not verification of the remote host providing a separate error stream is enabled.voidSame asrexec(user, password, command, false);voidRemotely executes a command through the rexecd daemon on the server to which the RExecClient is connected.final voidsetRemoteVerificationEnabled(boolean enable) Enable or disable verification that the remote host connecting to create a separate error stream is the same as the host to which the standard out stream is connected.Methods inherited from class org.apache.commons.net.SocketClient_connectAction_, addProtocolCommandListener, applySocketAttributes, checkOpenOutputStream, connect, connect, connect, connect, connect, connect, createCommandSupport, fireCommandSent, fireReplyReceived, getCharset, getCharsetName, getCommandSupport, getConnectTimeout, getDefaultPort, getDefaultTimeout, 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
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Field Details- 
NULL_CHAR- Since:
- 3.3
- See Also:
 
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DEFAULT_PORTThe default rexec port. Set to 512 in BSD Unix.- See Also:
 
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_errorStream_If a separate error stream is requested,_errorStream_will point to an InputStream from which the standard error of the remote process can be read (after a call to rexec()). Otherwise,_errorStream_will be null.
 
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Constructor Details- 
RExecClientpublic RExecClient()The default RExecClient constructor. Initializes the default port toDEFAULT_PORT.
 
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Method Details- 
disconnectDisconnects from the server, closing all associated open sockets and streams.- Overrides:
- disconnectin class- SocketClient
- Throws:
- IOException- If an error occurs while disconnecting.
 
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getErrorStreamReturns the InputStream from which the standard error of the remote process can be read if a separate error stream is requested from the server. Otherwise, null will be returned. The error stream will only be set after a successful rexec() invocation.- Returns:
- The InputStream from which the standard error of the remote process can be read if a separate error stream is requested from the server. Otherwise, null will be returned.
 
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getInputStreamReturns the InputStream from which the standard output of the remote process can be read. The input stream will only be set after a successful rexec() invocation.- Returns:
- The InputStream from which the standard output of the remote process can be read.
 
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getOutputStreamReturns the OutputStream through which the standard input of the remote process can be written. The output stream will only be set after a successful rexec() invocation.- Returns:
- The OutputStream through which the standard input of the remote process can be written.
 
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isRemoteVerificationEnabledReturn whether or not verification of the remote host providing a separate error stream is enabled. The default behavior is for verification to be enabled.- Returns:
- True if verification is enabled, false if not.
 
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rexecSame asrexec(user, password, command, false);- Parameters:
- user- the user name
- password- the password
- command- the command to run
- Throws:
- IOException- if an error occurs
 
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rexecpublic void rexec(String user, String password, String command, boolean separateErrorStream) throws IOException Remotely executes a command through the rexecd daemon on the server to which the RExecClient is connected. After calling this method, you may interact with the remote process through its standard input, output, and error streams. You will typically be able to detect the termination of the remote process after reaching end of file on its standard output (accessible throughgetInputStream()). Disconnecting from the server or closing the process streams before reaching end of file will not necessarily terminate the remote process.If a separate error stream is requested, the remote server will connect to a local socket opened by RExecClient, providing an independent stream through which standard error will be transmitted. RExecClient will do a simple security check when it accepts a connection for this error stream. If the connection does not originate from the remote server, an IOException will be thrown. This serves as a simple protection against possible hijacking of the error stream by an attacker monitoring the rexec() negotiation. You may disable this behavior with setRemoteVerificationEnabled().- Parameters:
- user- The account name on the server through which to execute the command.
- password- The plain text password of the user account.
- command- The command, including any arguments, to execute.
- separateErrorStream- True if you would like the standard error to be transmitted through a different stream than standard output. False if not.
- Throws:
- IOException- If the rexec() attempt fails. The exception will contain a message indicating the nature of the failure.
 
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setRemoteVerificationEnabledEnable or disable verification that the remote host connecting to create a separate error stream is the same as the host to which the standard out stream is connected. The default is for verification to be enabled. You may set this value at any time, whether the client is currently connected or not.- Parameters:
- enable- True to enable verification, false to disable verification.
 
 
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