java - 使用 apache-commons-net TelnetClient 发送终端命令时如何禁用回显

Question

所以，我有一个使用 org.apache.commons.net.telnet.TelnetClient 的类类(class)。它尝试发送命令并读取响应。

public class AutomatedTelnetClient
{
    private TelnetClient telnet = new TelnetClient();
    private InputStream in;
    private PrintStream out;
    private String prompt = "$";

    public AutomatedTelnetClient(String server, String user, String password)
    {
        try
        {
            EchoOptionHandler echoopt = new EchoOptionHandler(false, false, false, false);
            telnet.addOptionHandler(echoopt);

            // Connect to the specified server
            telnet.connect(server, 23);

            // Get input and output stream references
            in = telnet.getInputStream();
            out = new PrintStream(telnet.getOutputStream());

            // Log the user on
            readUntil("login: ");
            write(user);
            readUntil("Password: ");
            write(password);

            // Advance to a prompt
            readUntil(prompt + " ");
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public void su(String password)
    {
        try
        {
            write("su");
            readUntil("Password: ");
            write(password);
            prompt = "#";
            readUntil(prompt + " ");
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public String readUntil(String pattern)
    {
        try
        {
            char lastChar = pattern.charAt(pattern.length() - 1);
            StringBuffer sb = new StringBuffer();
            boolean found = false;
            char ch = (char) in.read();
            while (true)
            {
                System.out.print(ch);
                sb.append(ch);
                if (ch == lastChar)
                {
                    if (sb.toString().endsWith(pattern))
                    {
                        return sb.toString();
                    }
                }
                ch = (char) in.read();
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

    public void write(String value)
    {
        try
        {
            out.println(value);
            out.flush();
            System.out.println(value);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public String sendCommand(String command)
    {
        try
        {
            write(command);
            return readUntil(prompt + " ");
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

    public void disconnect()
    {
        try
        {
            telnet.disconnect();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public static void main(String[] args)
    {
        try
        {
            AutomatedTelnetClient telnet = new AutomatedTelnetClient(
                    "...", "...", "...");

            System.out.println("Got Connection...");

            System.out.println("run command");
            telnet.sendCommand("ls ");
            telnet.sendCommand("cd netConf");
            telnet.sendCommand("ls ");
            telnet.sendCommand("cd lanSetup");
            telnet.sendCommand("ls ");
            telnet.sendCommand("cd dhcpd");
            telnet.sendCommand("show interface 2");

            telnet.disconnect();
            System.out.println("DONE");
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

问题是，当我发送命令时，响应以某种回声开头。例如，当我发送 ls 命令时，这是我读取的响应

[mls 
....

我试过在 how to disable echo 上搜索，但似乎没有人知道答案。所以，我决定询问这个社区。有谁知道如何禁用此回声？

编辑

查看EchoOptionHandler的源代码让我感到困惑。为什么子协商方法只返回 null？

Answer 1

有趣的问题。总结一下我的努力:我没有让它正常工作但这里有一些我的发现:

您不能将 IAC DON'T ECHO 直接写入数据通道，这是通过此示例中的命令和选项完成的

int[] msg = {TelnetCommand.DONT,TelnetOption.ECHO};
telnet.sendSubnegotiation(msg);

您可以注册 telnet.registerNotifHandler(new MyNotificationHandler()); 以在连接设置期间调试命令

public class MyNotificationHandler implements TelnetNotificationHandler
{
  @Override
  public void receivedNegotiation(int negotiation_code, int option_code)
  {
    System.out.println("--->"+get(negotiation_code)+" "
                             +TelnetOption.getOption(option_code));
  }

  private String get(int i)
  {
    if(i==TelnetNotificationHandler.RECEIVED_DO){return "RECEIVED_DO";}
    else if(i==TelnetNotificationHandler.RECEIVED_DONT){return "RECEIVED_DONT";}
    else if(i==TelnetNotificationHandler.RECEIVED_WILL){return "RECEIVED_WILL";}
    else if(i==TelnetNotificationHandler.RECEIVED_WONT){return "RECEIVED_WONT";}
    else if(i==TelnetNotificationHandler.RECEIVED_COMMAND)
                                                    {return "RECEIVED_COMMAND";}
    return "UNKNOWN";
    }
}