telnetwrapper.java

The Javatm Telnet Application/Applet 很好用的

/*
 * This file is part of "The Java Telnet Application".
 *
 * (c) Matthias L. Jugel, Marcus Mei遪er 1996-2002. All Rights Reserved.
 *
 * Please visit http://javatelnet.org/ for updates and contact.
 *
 * --LICENSE NOTICE--
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * --LICENSE NOTICE--
 *
 */

package de.mud.telnet;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.net.Socket;

import java.util.Vector;
import java.util.Properties;

import java.awt.Dimension;

import de.mud.jta.Wrapper;

/**
 * The telnet wrapper is a sample class for how to use the telnet protocol
 * handler of the JTA source package. To write a program using the wrapper
 * you may use the following piece of code as an example:
 * <PRE>
 *   TelnetWrapper telnet = new TelnetWrapper();
 *   try {
 *     telnet.connect(args[0], 23);
 *     telnet.login("user", "password");
 *     telnet.setPrompt("user@host");
 *     telnet.waitfor("Terminal type?");
 *     telnet.send("dumb");
 *     System.out.println(telnet.send("ls -l"));
 *   } catch(java.io.IOException e) {
 *     e.printStackTrace();
 *   }
 * </PRE>
 * Please keep in mind that the password is visible for anyone who can
 * download the class file. So use this only for public accounts or if
 * you are absolutely sure nobody can see the file.
 * <P>
 * <B>Maintainer:</B> Matthias L. Jugel
 *
 * @version $Id: TelnetWrapper.java,v 1.13 2003/04/26 12:33:29 marcus Exp $
 * @author Matthias L. Jugel, Marcus Mei遪er
 */
public class TelnetWrapper extends Wrapper {
  protected TelnetProtocolHandler handler;

  /** debugging level */
  private final static int debug = 0;

  public TelnetWrapper() {
    handler = new TelnetProtocolHandler() {
      /** get the current terminal type */
      public String getTerminalType() {
        return "vt320";
      }

      /** get the current window size */
      public Dimension getWindowSize() {
        return new Dimension(80, 25);
      }

      /** notify about local echo */
      public void setLocalEcho(boolean echo) {
        /* EMPTY */
      }

      /** write data to our back end */
      public void write(byte[] b) throws IOException {
        out.write(b);
      }

      /** sent on IAC EOR (prompt terminator for remote access systems). */
      public void notifyEndOfRecord() {
      }
    };
  }

  public TelnetProtocolHandler getHandler() {
    return handler;
  }
  
  public void connect(String host, int port) throws IOException {
    super.connect(host, port);
    handler.reset();
  }

  /**
   * Send a command to the remote host. A newline is appended and if
   * a prompt is set it will return the resulting data until the prompt
   * is encountered.
   * @param cmd the command
   * @return output of the command or null if no prompt is set
   */
  public String send(String cmd) throws IOException {
    byte arr[];
    arr = (cmd + "\n").getBytes();
    handler.transpose(arr);
    if (getPrompt() != null)
      return waitfor(getPrompt());
    return null;
  }

  /**
   * Read data from the socket and use telnet negotiation before returning
   * the data read.
   * @param b the input buffer to read in
   * @return the amount of bytes read
   */
  public int read(byte[] b) throws IOException {
    int n = handler.negotiate(b);

    if (n > 0)
      return n;

    while (n <= 0) {
      do {
        n = handler.negotiate(b);
        if (n > 0)
          return n;
      } while (n == 0);
      n = in.read(b);
      if (n < 0)
        return n;
      handler.inputfeed(b, n);
      n = handler.negotiate(b);
    }
    return n;
  }
}