waitFor after exec never returns
Sometimes, when I create a process with Runtime.exec, waitFor never
returns, even though I'm clearing the error and output streams.
Here is my code, with important lines starred:
static void shexec(String command) throws
InternalErrorException {
String[]
commandArray = {"/bin/sh", "-c", command};
String[]
envArray = {"TERM=vt100"};
Log.logMessage("About
to call exec");
try
{
Log.logMessage("/bin/sh -c " + command);
Process p =
Runtime.getRuntime().exec(commandArray, envArray);
InputStream is = p.getErrorStream();
byte cbuf[] = new byte[1024];
int len;
while ((len = is.read(cbuf, 0, 1024)) != -1) {
if
(len > 0) {
String errorMessage = new String(cbuf, 0, len);
Log.logMessage("Read " + len + " bytes from
ErrorStream:" + errorMessage);
throw new InternalErrorException(errorMessage);
}
}
Log.logMessage("Done with ErrorStream");
is = p.getInputStream();
while ((len = is.read(cbuf, 0, 1024)) != -1)
Log.logMessage("Read
" + len + " bytes from InputStream");
Log.logMessage("Done with InputStream");
p.getOutputStream().close();
Log.logMessage("About to call waitFor");
p.waitFor();
Log.logMessage("Return value is " + p.exitValue());
Log.logMessage("Back from waitFor");
} catch (Exception e) {
Log.logMessage("Exception occurred: " + e);
throw new InternalErrorException(e);
}
}
My log file reads:
About to call exec
/bin/sh -c lynx -dump -force_html
/home/systers/javamlm/archive/94.text-html >
/home/systers/javamlm/archive/94.text-plain
Done with ErrorStream
Done with InputStream
About to call waitFor
I am using:
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build
Blackdown-1.3.0-FCS)
Java HotSpot(TM) Client VM (build Blackdown-1.3.0-FCS, mixed mode)
ps shows the process as being defunct.
This has been frustrating me for a long time.
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Re: waitFor after exec never returns
Thanks for the reply. >Lynx isn't a shell script, you can invoke it directly in the exec() call. The reason I don't invoke lynx directly is because I am redirecting its output to a file, which of course requires a shell. I think that was obscured by some bad line breaks in my original message. Let's see if this is any clearer: /bin/sh -c lynx -dump -force_html 94.text-html > 94.text-plain Ellen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: waitFor after exec never returns
At 03:31 PM 5/18/2001 -0500, you wrote: >Yes, I noticed the redirection. Have you actually LOOKED at 94.text-plain >when you invoke this command string manually? It generates the right output when I can lynx directly but not when I pass it through a shell. I hadn't realized that lynx would behave differently depending how it was invoked, as long as environment variables were set properly. Thanks for pointing that out. > lynx -dump -force_html 94.text-html > 94.text-plain > >does exactly what you want. Yes, but I can't give that as an argument to Runtime.exec, because it includes redirection. Do you know how to get lynx to do what I want (convert a html file into text)? Ellen Spertus -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: waitFor after exec never returns
At 09:57 PM 5/18/2001 -0500, Joi Ellis wrote: >Lynx is writing the rendered text to stdout, which you're reading and >throwing away. Why not read it and write it to the file yourself? I thought doing it with redirection would be simpler, but apparently not. I rewrote it so my program grabs the lynx output directly, and all works. I still get a hang on p.waitFor, so I replaced it with p.destroy (after I've read the strings). I'd still like to know why waitFor isn't working, but I'm happy my program is running. Thanks for your assistance. Ellen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
