import org.apache.commons.net.telnet.InvalidTelnetOptionException; //导入依赖的package包/类
public void open(String host, int port) throws IOException {
    // Synchronized block prevents listener thread from attempting to read input before we're ready.
    synchronized (this.charBuffer) {
        this.telnetClient.connect(host, port);
        this.telnetClient.setKeepAlive(true);

        if (this.suppressGAOptionHandler == null) {
            // Only do this once.
            this.suppressGAOptionHandler = new SuppressGAOptionHandler(true, true, true, true);

            try {
                this.telnetClient.addOptionHandler(this.suppressGAOptionHandler);
            } catch (InvalidTelnetOptionException e) {
                // Should never happen. Wrap it inside IOException so as not to declare another throwable.
                throw new IOException(e);
            }
        }

        this.reader = new BufferedReader(new InputStreamReader(this.telnetClient.getInputStream()));
        this.outstream = new PrintStream(this.telnetClient.getOutputStream());
    }
}
 

import org.apache.commons.net.telnet.InvalidTelnetOptionException; //导入依赖的package包/类
public void setOptionHandler(TelnetOptionHandler handler) throws IOException, InvalidTelnetOptionException {
  checkNotConnected();
  client.addOptionHandler(handler);
}