Command Line

[dougie1809]

Hi,

I have a method working fine that runs and executes command line arguments using the Process, Runtime and StreamPumpter classes with certain methods, the code is referred below. The problem is, when i try running the 'dir' command, it doesn't return any directories or files when I test it under main method? Although other commands work fine.
I'm assuming it cant find where its trying to look?
Thanks.

static int execCmd(String cmdLine) throws Exception
{
Process process = Runtime.getRuntime().exec(cmdLine);

StreamPumper outPumper = new StreamPumper(process.getInputStream(), System.out);

StreamPumper errPumper = new StreamPumper(process.getErrorStream(), System.err);

outPumper.start();

errPumper.start();

process.waitFor();

outPumper.join();

errPumper.join();

return process.exitValue();
}

[pbrockway2]

Does the method throw any exception? What is it?

[DarrylBurke]

How to execute dir command from Java

db

[dougie1809]

Yes, they throw IOException and InterruptedException exceptions.
IOException is for the Runtime exec() method.
InterruptedException is for the Process methods.

Would that matter?

[pbrockway2]

Yes, exceptions matter because they can be quite informative. The IOException comes with a message that more or less says what the problem is. It's a little cryptic, as such messages tend to be, but ask if you can't understand it.

import java.io.IOException;

public class Foo {
    public static void main(String[] args) throws IOException {
        Runtime.getRuntime().exec("c:/Program Files/putty.exe");
        Runtime.getRuntime().exec("dir");
    }
}

"c:/Program Files/putty.exe" runs just fine, but "dir" throws an exception and says why.

[waiheng1986]

Yes, exceptions matter because they can be quite informative. The IOException comes with a message that more or less says what the problem is. It's a little cryptic, as such messages tend to be, but ask if you can't understand it.

import java.io.IOException;

public class Foo {
    public static void main(String[] args) throws IOException {
        Runtime.getRuntime().exec("c:/Program Files/putty.exe");
        Runtime.getRuntime().exec("dir");
    }
}

"c:/Program Files/putty.exe" runs just fine, but "dir" throws an exception and says why.

Code below is the example to execute the command in the command prompt.

import java.io.*; 

public class doscmd 
{ 
public static void main(String args[]) 
{ 
try 
{ 
Process p=Runtime.getRuntime().exec("cmd /c dir"); 
p.waitFor(); 
BufferedReader reader=new BufferedReader(new InputStreamReader(p.getInputStream())); 
String line=reader.readLine(); 
while(line!=null) 
{ 
System.out.println(line); 
line=reader.readLine(); 
} 

} 
catch(IOException e1) {} 
catch(InterruptedException e2) {} 

System.out.println("Done"); 
} 
}

Moderator edit: link removed.

[DarrylBurke]

I am writing a blog about learning Java from basic.
Kindly have a look if you are interested and raise up any question about Java in the blog and i will try to solve for it.
Click here to the blog
Moderator edit: link removed.

waheng, this is a forum, not a free advertising site. If you want to promote your blog, we have a section for Reviews/Advertising.

Any question about Java can as well be raised here as on your blog; rest assured that this forum has at least a few thousand times more readers.

If you want to contribute to this site, you're most welcome. In view of this early posting history, any links to your blog are liable to be removed, and repeatedly posting links to the blog may lead to a ban.

db

[waiheng1986]

waheng, this is a forum, not a free advertising site. If you want to promote your blog, we have a section for Reviews/Advertising.

Any question about Java can as well be raised here as on your blog; rest assured that this forum has at least a few thousand times more readers.

If you want to contribute to this site, you're most welcome. In view of this early posting history, any links to your blog are liable to be removed, and repeatedly posting links to the blog may lead to a ban.

db

Well, sorry for the my foolish action in this forum. Actually i am honestly trying to help on those having problem in java and just promote the blog when i reply.
I promise not to promote my blog in this forum and more and honest in solving others problem.

Sorry and hope you guys can welcome me.
Thank you