Re: How come I can't seem to load a jar file successfully?
In article <2t98k.11207$uE5.8772@flpi144.ffdc.sbc.com>,
Mark Space <markspace@sbc.global.net> wrote:
Roedy Green wrote:
On Tue, 24 Jun 2008 06:33:33 -0400, Jim <k4gvo@bellsouth.net> wrote,
quoted or indirectly quoted someone who said :
Especially since I don't even have jarlook installed.
the link was the download. You have been successful with jar.exe
flags, so never mind.
Those jar.exe flags are pretty easy to manipulate, for the most part.
Listing the contents of a jar file requires a very easy to remember
combination of two flags. Whereas jarlook requires that I remember the
path to jarlook, and do a lot more typing too. "java -jar
C:\path\to\file\jarlook.jar" and then add the arguments to jarlook, this
is not really easier than just the jar command.
I don't mean to pile up on you Roedy, just trying to explain why jarlook
isn't a great utility for replacing the basic jar utility. And grep is
available everywhere. I have it on my windows box courtesy of Cygwin,
and if I set the default windows path to point to the Cygwin binaries, I
have grep available in the regular Window's command prompt too.
Now if jarlook did other things besides what jar did, and if jarlook was
easier to add to the command line path with out the full java -jar
command, that would be something I could get behind.
I keep a few command-line jars in ~/bin with eponymous scripts to save
typing:
#!/bin/sh
java -jar ~/bin/<some>.jar "${@}"
As it's a common cause of jar problems, here's a class I use to examine
the manifest without having to extract it. It might make a good addition
to JarLook:
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
/**
* Display the manifest of a jar file.
* @author John B. Matthews
*/
public class Manifesto {
public static void main(String[] args) {
if (args.length < 1) showHelp();
else for (String name : args) try {
System.out.println("Manifest: " + name);
JarFile jar = new JarFile(name);
Manifest manifest = jar.getManifest();
if (manifest != null)
showMap(manifest.getMainAttributes());
} catch (Exception e) {
System.out.println(e.getMessage());
showHelp();
System.exit(1);
}
}
private static void showMap(Attributes map) {
for (Map.Entry<Object, Object> e : map.entrySet())
System.out.println(e.getKey() + ": " + e.getValue());
}
private static void showHelp() {
System.out.println(
"Usage: java Manifesto <jarfile> [<jarfile>]");
}
}
For amusement, try and guess what happened when I (carelessly) named the
class Manifest. :-)
--
John B. Matthews
trashgod at gmail dot com
home dot woh dot rr dot com slash jbmatthews