Re: Printing Problem

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 09 May 2009 15:09:19 -0400
Message-ID:
<gu4kd0$i8a$1@news.albasani.net>
ruds wrote:

I tried by calling the batch file too, the bat file runs ok when
executed.It also creates pdf when called from a standalone java app,
but fails to give output when the bat file is called through servlet.
My code when called through servlet:

p = Runtime.getRuntime().exec("cmd /c C:\\test.bat");
int iwaitfor = 240; //2 mins
while(iwaitfor > 0) //wait till thread dead or "iwaitfor" in time.
 iwaitfor--;


I don't know what you mean by "mins" in the comment, but that loop might take
literally no time at all, depending on what the optimizer does with it. At
most, on modern systems I'd expect it to take about a fraction of a
microsecond to execute.

FWIW, "iwaitfor" does not conform to the Java convention for variable names.

System.out.println("Sleep started");
Thread.sleep(3000);
System.out.println("Sleep ended");
p.destroy();


Perhaps three seconds isn't long enough for the execution of the batch file to
complete?

You'd be better off actually waiting for the execution than guessing about the
timing.

<http://java.sun.com/javase/6/docs/api/java/lang/Process.html#waitFor()>

stdInput = new BufferedReader(new InputStreamReader(p.getInputStream
()));

Even then the PDFCreator is just seen running without giving output
when called through servlet.


Interestingly, you kill the subprocess before you try to read its output.
I've not used 'Process', but that seems suspect to me.

--
Lew

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