using java to call and run python but no result. processbuilder runtime

Question

I tried both runtime and processbuilder to run python in java, but java cannot display the python result.

python code:

def cal():
    a=4
    b=90
    c=a+b
    return c


if __name__ == "__main__":
    c=cal()
    print c
    print "hello"
    print "hello..................."  

java code

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class qqqqqqqqqqqqqqqq {

    public static void main (String args[]) throws IOException {




        try
        {
//      ProcessBuilder pb = new ProcessBuilder("C:/Python27/python","C://Users//admin//Destop//dsf.py" );       
//      Process p = pb.start();

            Runtime r=Runtime.getRuntime();
            Process p=r.exec("cmd /c C:/Python27/python C://Users//admin//Destop//dsf.py");



            BufferedReader bfr = new BufferedReader(new InputStreamReader(p.getInputStream()));

            System.out.println(".........start   process.........");
            String line = "";
            while ((line = bfr.readLine()) != null)
                {
                    System.out.println("Python Output: " + line);
                }
            System.out.println("........end   process.......");

        } catch (Exception e)
        {
            System.out.println(e);
        }



 }
}

java output result:

.........start   process.........
........end   process.......

there is no error with the path and code, Why java cannot run the python ?

Answer 1

Your code is absolutely correct. Below are some of the corrections needed to run the python code in standard java program.

Use double slashes in providing python exe in Process p=r.exec("cmd /c C:/Python27/python C://Users//admin//Destop//dsf.py");

public class Test {

public static void main (String args[]) throws IOException {

    try
    {
        Runtime r=Runtime.getRuntime();
        Process p=r.exec("cmd /c C:\\Python34\\python.exe D:\\PythonScripts\\HelloWorld.py");

        BufferedReader bfr = new BufferedReader(new InputStreamReader(p.getInputStream()));

        System.out.println(".........start   process.........");
        String line = "";
        while ((line = bfr.readLine()) != null)
            {
                System.out.println("Python Output: " + line);
            }
        System.out.println("........end   process.......");

    } catch (Exception e)
    {
        System.out.println(e);
    }
   }
   }