使用Java时如何保持命令提示符处于打开状态？

Question

Here's my code:

import java.io.*;

public class PingTest
{
    public static void main (String [] args) throws IOException, InterruptedException
    {
        Runtime.getRuntime().exec(new String[]
           {"cmd","/k","start","cmd","/c","ping localhost"});
    }
}

It pings the localhost like I want it to, but it doesn't stay open. It closes right away once it's done. What do I do to fix that?

Answer 1

Since you're basically executing

cmd /k start cmd /c ping localhost

It does exactly what it should, runs start which runs cmd which terminates after ping finishes because of the /c flag.

If you want the window with the ping results to stay open you need to do

cmd /k start cmd /k ping localhost

or

cmd /c start cmd /k ping localhost

(Doesn't matter what the flag on the first cmd is because it isn't opening a new window.)

Answer 2

One cheap fix is to request input at the end of main().

public static void main (String [] args) throws IOException, InterruptedException
{
    ...

    System.out.println("Press return to continue.");
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    in.readLine();
}

Answer 3

You may want to use the built in command pause . For that you can extend you command like that:

public static void main (String [] args) throws IOException, InterruptedException
{
    Runtime.getRuntime().exec(new String[]
       {"cmd", "/k", "start", "cmd", "/c", "\"ping localhost & pause\""});
}