使用 JSch 为通过 SSH 执行的命令提供输入/子命令

Question

I'm trying to manage router via Java application using Jcraft Jsch library.

I'm trying to send Router Config via TFTP server. The problem is in my Java code because this works with PuTTY.

This my Java code:

int port=22;
String name ="R1";
String ip ="192.168.18.100";
String password ="root";

JSch jsch = new JSch();
Session session = jsch.getSession(name, ip, port);
session.setPassword(password);
session.setConfig("StrictHostKeyChecking", "no");
System.out.println("Establishing Connection...");
session.connect();
System.out.println("Connection established.");

ChannelExec channelExec = (ChannelExec)session.openChannel("exec");

InputStream in = channelExec.getInputStream();
channelExec.setCommand("enable");

channelExec.setCommand("copy run tftp : ");
//Setting the ip of TFTP server 
channelExec.setCommand("192.168.50.1 : ");
// Setting the name of file
channelExec.setCommand("Config.txt ");

channelExec.connect();

BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line;
int index = 0;
StringBuilder sb = new StringBuilder();
while ((line = reader.readLine()) != null)
{
    System.out.println(line);
}
session.disconnect();

I get

Line has an invalid autocommand '192.168.50.1'

The problem is how can I run those successive commands.

Answer 1

Calling ChannelExec.setCommand multiple times has no effect.

And even if it had, I'd guess that the 192.168.50.1 : and Config.txt are not commands, but inputs to the copy run tftp : command, aren't they?

If that's the case, you need to write them to the command input.

Something like this:

ChannelExec channel = (ChannelExec) session.openChannel("exec");
channelExec.setCommand("copy run tftp : ");
OutputStream out = channelExec.getOutputStream();
channelExec.connect();
out.write(("192.168.50.1 : \n").getBytes());
out.write(("Config.txt \n").getBytes());
out.flush();

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In general, it's always better to check if the command has better "API" than feeding the commands to input. Commands usually have command-line arguments/switches that serve the desired purpose better.

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A related question: Provide inputs to individual prompts separately with JSch .