I've created an executable jar and using commons-cli to give the user the ability to specify command line parameters when he launches the client. Everything works fine. However, when I print the usage statement for the jar, I would like to show the following:
usage: java -jar myprog.jar <options> <file>
--help Display the help message
--debug Enable debugging
....
Printing of all the options is easily done with commons-cli. However, the "usage" line is the head scratcher. I cannot seem to figure out a way to get the "myprog.jar" name from the args[] that are passed to the application.
Is there any easy way of doing this? I could use a pretty convoluted method to back trace from my class' classloader and figure out if it is contained within a jar, but that seems like a fairly ugly answer to what should be a pretty simple question.
private String getPath(Class cls) {
String cn = cls.getName();
String rn = cn.replace('.', '/') + ".class";
String path =
getClass().getClassLoader().getResource(rn).getPath();
int ix = path.indexOf("!");
if(ix >= 0) {
return path.substring(0, ix);
} else {
return path;
}
}
Here you go:
new java.io.File(SomeClassInYourJar.class.getProtectionDomain()
.getCodeSource()
.getLocation()
.getPath())
.getName()
Edit: I saw your comment about getSourceCode API. Well, this is probably the best you can do in Java. About getCodeSource()
returning null
, I think it mainly happens on classes in java.lang.*
and other special classes for which the source location is "hidden". Should work for your own classes though.