How to execute cmd commands via Java

Question

I am trying to execute command line arguments via Java. For example:

// Execute command String command = "cmd /c start cmd.exe"; Process child = Runtime.getRuntime().exec(command);  // Get output stream to write from it OutputStream out = child.getOutputStream();  out.write("cd C:/ /r/n".getBytes()); out.flush(); out.write("dir /r/n".getBytes()); out.close(); 

The above opens the command line but does not execute cd or dir. Any ideas? I am running Windows XP, JRE6.

(I have revised my question to be more specific. The following answers were helpful but do not answer my question.)

Answer 1

I found this in forums.oracle.com

Allows the reuse of a process to execute multiple commands in Windows: http://kr.forums.oracle.com/forums/thread.jspa?messageID=9250051

You need something like

   String[] command =     {         "cmd",     };     Process p = Runtime.getRuntime().exec(command);     new Thread(new SyncPipe(p.getErrorStream(), System.err)).start();     new Thread(new SyncPipe(p.getInputStream(), System.out)).start();     PrintWriter stdin = new PrintWriter(p.getOutputStream());     stdin.println("dir c:\\ /A /Q");     // write any other commands you want here     stdin.close();     int returnCode = p.waitFor();     System.out.println("Return code = " + returnCode); 

SyncPipe Class:

class SyncPipe implements Runnable { public SyncPipe(InputStream istrm, OutputStream ostrm) {       istrm_ = istrm;       ostrm_ = ostrm;   }   public void run() {       try       {           final byte[] buffer = new byte[1024];           for (int length = 0; (length = istrm_.read(buffer)) != -1; )           {               ostrm_.write(buffer, 0, length);           }       }       catch (Exception e)       {           e.printStackTrace();       }   }   private final OutputStream ostrm_;   private final InputStream istrm_; } 

Answer 2

If you want to run several commands in the cmd shell then you can construct a single command like this:

  rt.exec("cmd /c start cmd.exe /K \"cd c:/ && dir\""); 

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