How do you invoke a python script inside a jar file using python?

Question

I'm working on an application that intersperses a bunch of jython and java code. Due to the nature of the program (using wsadmin) we are really restricted to Python 2.1

We currently have a jar containing both java source and .py modules. The code is currently invoked using java, but I'd like to remove this in favor of migrating as much functionality as possible to jython.

The problem I have is that I want to either import or execute python modules inside the existing jar file from a calling jython script. I've tried a couple of different ways without success.

My directory structure looks like:

application.jar
  |-- com
       |--example
            |-- action
                 |-- MyAction.class
                 |-- pre_myAction.py

The 1st approach I tried was to do imports from the jar. I added the jar to my sys.path and tried to import the module using both import com.example.action.myAction and import myAction. No success however, even when I put init.py files into the directory at each level.

The 2nd approach I tried was to load the resource using the java class. So I wrote the below code:

import sys
import os
import com.example.action.MyAction as MyAction

scriptName = str(MyAction.getResource('/com/example/action/myAction.py'))
scriptStr = MyAction.getResourceAsStream('/com/example/action/myAction.py')

try:
  print execfile(scriptStr) 
except:
  print "failed 1"

try:
  print execfile(scriptName) 
except:
  print "failed 2"

Both of these failed. I'm at a bit of a loss now as to how I should proceed. Any ideas ?

cheers,

Trevor

In the jar file. Its on the classpath when I invoke jython. If I print sys.path you see it there. Just to be thorough I've tried adding the jar directly to the code using sys.path.append() but it did not make any difference. — Trevor
– Trevor, Commented Mar 31, 2010 at 8:12
Look at zipimport (docs.python.org/library/zipimport.html) and at the example at the bottom. When you write init.py, do mean __init__.py, right? — mg.
– mg., Commented Mar 31, 2010 at 9:15

Blauohr · Accepted Answer · 2010-03-31 10:51:39Z

5

the following works for me :

import sys
import os

import java.lang.ClassLoader 
import java.io.InputStreamReader
import java.io.BufferedReader

loader = java.lang.ClassLoader.getSystemClassLoader()
stream = loader.getResourceAsStream("com/example/action/myAction.py")
reader = java.io.BufferedReader(java.io.InputStreamReader(stream))

script = ""                          
line = reader.readLine()
while (line != None) : 
    script += line + "\n"
    line = reader.readLine()

exec(script)

Loading the Script from the ClassPath as a String in 'script'
exec the script with exec

answered Mar 31, 2010 at 10:51

Blauohr

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2 Comments

Trevor Over a year ago

That is a really good answer. I was hoping for something a bit simpler, but I think that this is likely to be the best option.

Amine CHERIFI Over a year ago

hello, could you please add how should we run this script. Thank you

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