Re: Runtime.exec(cmd) hangs up
I was wondering if its possible to read only stdout as a temporary fix
if its gonna work, would this hang up problem be still there if I just
do
Process proc = Runtime.getRuntime().exec(cmd);
BufferedReader in = new BufferedReader(new
InputStreamReader(proc.getInputStream()));
proc.waitfor (in the try catch block)
.........
.........
I actually tried the above version but didn't work
On May 24, 5:53 pm, "Mike Schilling" <mscottschill...@hotmail.com>
wrote:
"Vic" <vikra...@gmail.com> wrote in message
news:1180046607.237152.145810@r19g2000prf.googlegroups.com...
I am having a problem with Runtime.exec(cmd) where cmd is a string and
is as follows -
cmd = "home/qaplay/loader/604/soaploaderclient.ps nemo 50624 55604
genevaman qa /home/vpatanka/604Current/lib/loader/data/
DuplicateTransactionTest.0.lrd -bcp > & $GVHOME/tempOut.txt"
The actual code is like this ->
public CommandExecuter (String cmd) throws java.io.IOException{
System.out.println("CommandExecuter: EXECUTING COMMAND: "+cmd);
Process proc = Runtime.getRuntime().exec(cmd);
BufferedReader in = new BufferedReader(new
InputStreamReader(proc.getInputStream()));
BufferedReader err = new BufferedReader(new
InputStreamReader(proc.getErrorStream()));
stdout = "";
while ((line = in.readLine()) != null)
stdout += line +"\n";
if (stdout == "")
stdout = null;
stderr = "";
while ((line = err.readLine()) != null)
stderr += line +"\n";
if (stderr == "")
stderr = null;
//System.out.println ("CommandExecuter stdout="+stdout);
//System.out.println ("CommandExecuter stderr="+stderr);
}
}
I can run the same cmd on the shell and I get a an output which is
pretty big so I am not copying it over here but if you guyz need it
then I can do that. Please let me know what am I missing here in
Runtime.exec() or its something else
The obvious issue is that this code won't start to read stderr until the
exec'd process closes stdout, so the process may be hung trying to wite to
stderr. Try reading from stdout and stderr at the same time (in different
threads.) A nice, symmetrical way to do this is
1. Runtime.exec()
2. Start a thread that reads from stdout as long as there's anything to
read and then exits.
3. Start another thread that reads from stderr as long as there's
anything to read and then exits.
4. Process.waitFor();