How do I run a python 2.7 code from my Java?

Question

I have a Java Swing class from which I want my Java application to run a local python program after clicking a button. The following code does not run the executable python I have created.

 private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    try {
        // TODO add your handling code here:
        Process process = 
        Runtime.getRuntime().exec("C:\\Users\\User\\Desktop\\hello.exe");
    } catch (IOException ex) {
        Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
    }

}     

I have even tried running the python script file using:

     private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    try {

        Process p= Runtime.getRuntime().exec("C:\\Python27\\python.exe \"C:\\Users\\User\\Desktop\\hello.py\"");
    } catch (IOException ex) {
        Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
    }

}      

I have no errors yet neither does the job. I can run applications like notepad etc using the same syntax, however I cant with python and I'm unsure how to resolve this. Ps I do have Python 2.7 PATH in my environment variable. Also, the above are just the methods for the action performed by the buttons. I have all the other methods and main class in my full program.

Answer 1

    Process p= Runtime.getRuntime().exec("cmd /c /K \"C:\\Python27\\python.exe C:\\Users\\User\\Desktop\\hello.py\"");

do this way.. call the Python from cmd

---

I tried this simple example & it worked for me... Files : CallPython.java & hello.py

CallPython.java

import java.util.*;
import java.io.*;

class CallPython{

    public static void main(String args[]){

       try{
            Process proc= Runtime.getRuntime().exec("python hello.py");
            BufferedReader stdInput = new BufferedReader(new InputStreamReader(proc.getInputStream()));

            /*
            BufferedReader stdError = new BufferedReader(new InputStreamReader(proc.getErrorStream()));

            // read the output from the command
            System.out.println("Here is the standard output of the command:\n");
            String s = null;
            while ((s = stdInput.readLine()) != null) {
                System.out.println(s);
            }
            */

            stdInput.lines().forEach(System.out::println);
        }
        catch(IOException e){
            System.err.println("Error occured while executing an external process...");
        }
    }
}

hello.py

print('Hello...from python script');

Output:

 Hello...from python script