I'm building a simple program that executes a single command to a linux server using Ganymed for SSH2 library. Here is my code...
public class Main {
static Scanner reader = new Scanner(System.in);
public static void main(String[] args) throws IOException, InterruptedException{
String hostname; // = "192.168.1.241";
int port; // = 22
String username; // = "root";
String password;
String cmd; // = "echo 'Hello World'";
//ask user for hostname/IP
System.out.print("Enter hostname or IP: ");
hostname = reader.nextLine();
//ask user for port #
System.out.print("Enter port number: ");
port = reader.nextInt();
//create connection
Connection connect = new Connection(hostname, port);
//ask user for username
System.out.println("Enter Username (best to use 'root'): ");
username = reader.nextLine();
//ask user for password
System.out.println("Enter Password: ");
password = reader.nextLine();
System.out.println("Attempting to log in...");
reader.close();
//establish connection
connect.connect();
//login using password
connect.authenticateWithPassword(username, password);
Thread.sleep(1000);
if (Thread.interrupted()) // Clears interrupted status!
throw new InterruptedException();
Boolean didConnect = connect.isAuthenticationComplete();
if (didConnect==false){
throw new IOException("Authentication Unsucessful \nCheck hostname and port number, then try again.");
}
//open session
Session session = connect.openSession();
System.out.println("Opened session!");
System.out.println("Enter a command to execute: ");
cmd = reader.nextLine();
//execute command
session.execCommand(cmd);
//get output
InputStream stdout = new StreamGobbler(session.getStdout());
BufferedReader br = new BufferedReader(new InputStreamReader(stdout));
String line = br.readLine();
if (line!=null){
System.out.println("Command sent succesfully!" + "\nOutput: " + "\n" + "\n" + line);
}else{
System.out.println("Command sent succesfully!" + "\nNo Output");
}
//close buffered reader
br.close();
//close session
session.close();
//close connection
connect.close();
}
}
For some reason...
//ask user for username
System.out.println("Enter Username (best to use 'root'): ");
username = reader.nextLine();
//ask user for password
System.out.println("Enter Password: ");
password = reader.nextLine();
print at the same time and I don't know why! It also gets the user input on a completely different line instead of right next to it when using print ln and on the same line when using print .
I want them to ask for the username first and then for password, putting the user input next to the output. However, when I ask for the hostname and port number they print individually/in order, like I want it to. What am I doing wrong?
After you do port = reader.nextInt();
, you need to place a reader.nextLine()
to read the rest of the line(and newline character) which has the int.
//ask user for port #
System.out.print("Enter port number: ");
port = reader.nextInt();
reader.nextInt()
doesn't read newline or anything after the number.
Add reader.nextLine()
then the rest of the code should follow:
reader.nextLine();
//ask user for username
System.out.println("Enter Username (best to use 'root'): ");
username = reader.nextLine();
//ask user for password
System.out.println("Enter Password: ");
password = reader.nextLine();
Your problem is that you're using the same Scanner object multiple times to read a line. It skips the code:
//ask user for username
System.out.println("Enter Username (best to use 'root'): ");
username = reader.nextLine();
//ask user for password
System.out.println("Enter Password: ");
password = reader.nextLine();
because the object already has a value for the method you're calling.
Solution: re-instantiate the object every time you use it:
reader = new Scanner(System.in);
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