I/O redirection in Eclipse?

Question

Is it possible to use I/O redirection in Eclipse?

I want to redirect standard input/output on the command line like java MyProgram <input.txt >output.txt, but I can't seem to get it to work in Eclipse. I tried including the <'s as part of the program arguments, which was ignored, and also in the VM arguments, which just threw up a class not found error. How can I do this?

Answer 1

To truly redirect both, the simplest way is still to define your program as an external script

 "java %1 %2 %3 %4 < %5 > %6"

(adapt the number of parameters to your particular program)

In the Run menu, click 'External Tools.../Open External Tools Dialog" and define an external launch configuration in which you will specify both the arguments and the input and output file.

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It is not an ideal solution though, as you cannot debug directly your code (with a "debug" launcher configuration).
Instead you have to remote debug it (add '-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000' in your generic Java launcher script)

Once you have launched your external tool, launch a remote debug session through the "debug launcher 'Remote Java Application'" section:

Answer 2

You can redirect output using the Run dialog, Common tab, "Standard Input and Output" section.

However, it doesn't look like you can redirect input as far as I can tell (and as far as this Stack Overflow question can tell, too).

How much control do you have over your application? If you don't mind a bit of a hack, you could have a couple of properties or command line arguments to determine the appropriate files, and use System.setOut and System.setIn accordingly. It is a bit of a hack though...