Changing the program's current directory.

[Dave Rudolf]

Hey all,

I am writing a java program that is really a front-end to a handful of other
programs, each in a different location of a directory tree. Some of the
programs have data files that they look for w.r.t. their current directory.
Now, when I call
Runtime.exec( "some_dir\\some_program.exe" );
it starts the program, but has it running from whatever the java program's
current directory is. Thus, the programs can't find the data files that they need.

So, I can get the current directory by doing
System.getProperty( "user.dir" );
But, apparently I can't just do
System.setProperty( "user.dir", "some_dir" );
It seems that doing so changes the system property at least as far as the
property map is concerned, but it does not affect the actual working directory.

So, how might I actually get the thing to change directories?

Thanks.

Dave

 

[Gordon Beaton]

Now, when I call
Runtime.exec( "some_dir\\some_program.exe" );
it starts the program, but has it running from whatever the java
program's current directory is. Thus, the programs can't find the
data files that they need.
[...]

So, how might I actually get the thing to change directories?

You can't change the working directory of the JVM, but you don't need
to in order to achieve what you've described.

Runtime.exec() lets you specify a working directory for the target
process.

/gordon

 

[Daniel Pitts]

Hey all,

I am writing a java program that is really a front-end to a handful of other
programs, each in a different location of a directory tree. Some of the
programs have data files that they look for w.r.t. their current directory.
Now, when I call
Runtime.exec( "some_dir\\some_program.exe" );
it starts the program, but has it running from whatever the java program's
current directory is. Thus, the programs can't find the data files that they need.

So, I can get the current directory by doing
System.getProperty( "user.dir" );
But, apparently I can't just do
System.setProperty( "user.dir", "some_dir" );
It seems that doing so changes the system property at least as far as the
property map is concerned, but it does not affect the actual working directory.

So, how might I actually get the thing to change directories?

Thanks.

Dave

Instead of using Runtime.exec, look into ProcessBuilder.
Both approaches let you run the program in a specific working
directory, but ProcessBuilder is more flexible in how you do it.