Use Java program from Python

Question

I'm using Python to launch a java program and to extract its results using os.system

os.system("java myprogram")

The problem is this launch the program on console and I have to type command inside the program to extract the result.

Do somebody know how to give command to the java program from Python ?

Thank you,

Answer 1

Easy way to invoke java program or any other script is using subprocess in python.

The subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes. This module intends to replace several older modules and functions

Read more about subprocess

Example:

subprocess.Popen - Following will invoke your script in background.

subprocess.Popen(["java", "ProgramPath/filename.java", "arg1", "arg2", "arg3"])

subprocess.call - And this will wait for the command to complete.

subprocess.call(["java", "ProgramPath/filename.java", "arg1", "arg2", "arg3"])

subprocess.check_output - will return you the output

output = subprocess.check_output(["java", "ProgramPath/filename.java", "arg1"])

Answer 2

http://www.jython.org/jythonbook/en/1.0/JythonAndJavaIntegration.html

This chapter will focus on integrating Java and Python, but it will explore several different angles on the topic. You will learn several techniques to make use Jython code within your Java applications. Perhaps you’d like to simplify your code a bit; this chapter will show you how to write certain portions of your code in Jython and others in Java so that you can make code as simple as possible.

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