Java app launch dir?

[Michael Brown]

How can my standalone Java app discover what directory it lives in? I want
to have the app look in that directory for a default properties file. I
don't think this is necessarily what is returned by
System.getProperty("user.dir"), is it? BTW, app is in a jar, so I'm looking
for what directory the jar is in.

Thanks....

Mike

 

[KC Wong]

How can my standalone Java app discover what directory it lives in? I
want

to have the app look in that directory for a default properties file. I
don't think this is necessarily what is returned by
System.getProperty("user.dir"), is it? BTW, app is in a jar, so I'm looking
for what directory the jar is in.

If your properties file are in the same directory as the JAR, then you don't
need to know where exactly it is...

Take a look at the Java API docs, about java.lang.Class, methods
getResource() and getResourceAsStream().

e.g.

private static final String PROGRAM_CONFIG = "/config.ini";

class Foo {
public Foo() {
InputStream configStream =
getClass().getResourceAsStream(PROGRAM_CONFIG);
}
}

 

[Liz]

If your properties file are in the same directory as the JAR, then you don't
need to know where exactly it is...

Take a look at the Java API docs, about java.lang.Class, methods
getResource() and getResourceAsStream().

e.g.

private static final String PROGRAM_CONFIG = "/config.ini";

class Foo {
public Foo() {
InputStream configStream =
getClass().getResourceAsStream(PROGRAM_CONFIG);
}
}

I do something like this
File dir = new File(".");
but that gives me the directory where the "java" command was issued
not necessarily the same as where the jar file lives.

 

[Alan Moore]

How can my standalone Java app discover what directory it lives in? I want
to have the app look in that directory for a default properties file. I
don't think this is necessarily what is returned by
System.getProperty("user.dir"), is it? BTW, app is in a jar, so I'm looking
for what directory the jar is in.

Thanks....

Mike

String s = MyApp.class.getResource("MyApp.class").getFile();
s = s.substring(5, s.indexOf("!"));
File installDir = new File(s.substring(0, s.lastIndexOf("/")));

 

[Jacob]

How can my standalone Java app discover what directory it lives in? I want
to have the app look in that directory for a default properties file. I
don't think this is necessarily what is returned by
System.getProperty("user.dir"), is it? BTW, app is in a jar, so I'm looking
for what directory the jar is in.

The common approach is to put the properties file
*inside* the jar. This works fine for site specific
deployment configuration etc. To ease the deployment
process, you might put it into a separate jar file
(app.jar + someCustomer.jar) which will be equivalent
as seen from your application.

This may however not be appropriate for all situations:
User preferences is updated per session, and should
live on the client machine. However, you have no
knowledge of the directory of your jar file, and it
is a bad idea to look there anyway. Using "user.dir"
is one option, but using the Preferences API from the
JDK is a lot better.