如何在Jython / Java代码中提供python包路径？

Question

I have taken a written sample from this link to write my Python + Java integration code.

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

The code looks like below.

package org.jython.book.interfaces;

import org.jython.book.interfaces.JythonObjectFactory;
import org.python.core.Py;
import org.python.core.PyString;
import org.python.core.PySystemState;

public class Main {

    public static void main(String args[]) {

        String projDir = System.getProperty("user.dir");
        String rootPath = projDir + "/src/org/jython/book/interfaces/";
        String modulesDir = projDir + "/src/org/jython/book/interfaces/";

        System.out.println("Project dir: " + projDir);

        PySystemState sysSt = Py.getSystemState();
        JythonObjectFactory factory = new JythonObjectFactory(sysSt, BuildingType.class, "Building", "Building");

        BuildingType building = (BuildingType) factory.createObject();

        building.setBuildingName("BUIDING-A");
        building.setBuildingAddress("100 MAIN ST.");
        building.setBuildingId(1);

        System.out.println(building.getBuildingId() + " " +
            building.getBuildingName() + " " +
            building.getBuildingAddress());
    }

}

When I run this code, it throws an error that it did not find the python module. I have kept the .py and .pyc files under the path provided as 'modulesDir'.

The literature says that "the requested module must be contained somewhere on the sys.path" ; however, I did not understand how this can be set from this Java program. Can someone please provide some help?

Project dir: /Users/eclipsews/PythonJava
Exception in thread "main" ImportError: No module named Building

Answer 1

Hi found the answer to this issue!

Added the PySystemState.initialize method where I explicitly provide the "python.path" property, which is initialized to my project's path, where python modules are available.

private static Properties setDefaultPythonPath(Properties props) {

    String pythonPathProp = props.getProperty("python.path");
    String new_value;

    if (pythonPathProp == null) {
        new_value  = System.getProperty("user.dir") + "/src/org/jython/book/interfaces/";       
    }

    props.setProperty("python.path", new_value);
    return props;
}

Properties props = setDefaultPythonPath(System.getProperties());
PySystemState.initialize( System.getProperties(), props, null );

This produces the correct output as follows:

module=<module 'Building' from '/Users/eclipsews/PythonJava/src/org/jython/book/interfaces/Building$py.class'>,class=<class 'Building.Buildin
g'>
1 BUIDING-A 100 MAIN ST.