Passing java jar output to python in an efficient way

Question

I am trying to speed up the way I call a java jar from python by saving the resulting string (java does System.out.println) in a python list. It used to write to directl to a file from java, but I found that was very slow, opening and closing the file each time, so trying to speed it up.

I currently have:

subprocess.call(
            ['java', '-jar', 'TensionTwoSlices.jar', '-runtype', '"groundtruth"', '-inputwindow', inputwindow, '-outputwindow', groundtruth,
             '-inputfile', '"not.txt"', '-key', '"C"'],stdout=subprocess.PIPE, stderr=subprocess.PIPE);

I read here that I can use STDOUT, so I tried:

 p = subprocess.Popen(
                ['java', '-jar', 'TensionTwoSlices.jar', '-runtype', '"groundtruth"', '-inputwindow', inputwindow, '-outputwindow', groundtruth,
                 '-inputfile', '"not.txt"', '-key', '"C"'],stdout=subprocess.STDOUT, stderr=subprocess.PIPE);


        print p.STDOUT;

but I am getting:

Traceback (most recent call last):
  File "extract_tension.py", line 65, in <module>
    '-inputfile', '"not.txt"', '-key', '"C"'],stdout=subprocess.STDOUT, stderr=subprocess.PIPE);
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1335, in _execute_child
    raise child_exception
OSError: [Errno 9] Bad file descriptor

As I am not longer writing to a file I believe I can switch from call to Popen.

But it's essential that nothing is written to the terminal as speed is extremely important (running this millions of times).

What is the fastest way of passing the System.out.println from java to a python list?

Jack Yang · Accepted Answer · 2017-08-20 05:53:16Z

0

Try -

output = subprocess.check_output(
    ['java', '-jar', 'TensionTwoSlices.jar', '-runtype', 
     '"groundtruth"', '-inputwindow', inputwindow, '-outputwindow', 
     groundtruth, '-inputfile', '"not.txt"', '-key', '"C"'])

print output

answered Aug 20, 2017 at 5:53

Jack Yang

3091 silver badge8 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Passing java jar output to python in an efficient way

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related