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Interpreting JAR's launched with parameters

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Interpreting JAR's launched with parameters

Jan 6th, 2009

Hey guys,
I am trying to get some code to interpret a parameter determined by a JAR file.

IE.
C:\user\myProgram.jar 500
I want to know how to transfer 500 over to the program. I googled it, and most of the stuff that came up was extremely difficult to understand.

Thanks PO

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Re: Interpreting JAR's launched with parameters

Jan 7th, 2009

To tell you the truth, I don't know what you mean "interpret a parameter determined by a JAR file".

If it is simply to be an argument on the command line, then, of course, args[0].

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Re: Interpreting JAR's launched with parameters

Jan 7th, 2009

args[0] ?

Sorry i am confused, here I will give you a small rundown of the program. I use a program to automatically log myself into Steam. With steam you can launch their games by saying C:\Steam\steam.exe -login username password -applaunch 500 and of course the login and application vary between games. So I have a bunch of icons on my desktop that go to a JAR that logs me into steam automatically, but then I have to launch the game from inside of steam, so I want to know how to launch a JAR and have the jar grab the parameter. Basically I want to say C:\user\thatProgram.jar -500 and have the program look for the parameter and if it's there make it a int inside of my program.

Thanks Jon

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Re: Interpreting JAR's launched with parameters

Jan 7th, 2009

Now if you have ever written a main, in your Java program, we write it as :-

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 java Syntax (Toggle Plain Text) 
public static void main(String args[]) {
public static void main(String args[]) {

Here the args, is an array containing the parameters you provided at the command line.

Consider the following example :-

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 java Syntax (Toggle Plain Text) 
public class CommandLineArgEx {
 
    public static void main(String[] args) {
        for(int i=0;i<args.length;i++) {
            System.out.println("Argument Number " + (i+1) + " : " + args[i]);
        }
    }
 
}
public class CommandLineArgEx {

    public static void main(String[] args) {
        for(int i=0;i<args.length;i++) {
            System.out.println("Argument Number " + (i+1) + " : " + args[i]);
        }
    }

}

Following would be the output that you will get :-

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 Java Syntax (Toggle Plain Text) 
stephen@steve:~/Development/java/daniweb> java CommandLineArgEx ABC Bcd Efg
Argument Number 1 : ABC
Argument Number 2 : Bcd
Argument Number 3 : Efg
stephen@steve:~/Development/java/daniweb>
stephen@steve:~/Development/java/daniweb> java CommandLineArgEx ABC Bcd Efg
Argument Number 1 : ABC
Argument Number 2 : Bcd
Argument Number 3 : Efg
stephen@steve:~/Development/java/daniweb>

So as you see whatever is passed via the command line, is stored in the args[] String array.
Although I have never tried it with a JAR, I do not see why it should not work.

Last edited by stephen84s; Jan 7th, 2009 at 2:12 pm.

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