Integrating Python into Java - can we call .py files directly?

Question

I am trying to understand Jython. I have some algorithms written in Python that I want to integrate in Java. The Jython docs are very complex for me to understand. All I could get from them is that I can run individual Python statements from Java by embedding them like this:

interp = new PythonInterpreter();
 interp.exec("import sys");
 interp.exec("print sys");

But I can't embed my giant algorithms like that. I need to run the py scripts. Is there any way to do that? Can I get a hello world example where the print("hello") statement is written in a py script file and the output is shown on a Java console?

• mzjn: Can't you use PythonInterpreter.execfile()? See jython.org/javadoc/org/python/util/….

Answer 1

Jython its the better option

else you can run python program from the java using the command prompt and collect the output back in java

as eg:

 ProcessBuilder builder = new ProcessBuilder(
 "cmd.exe", "/c", "C:\\Python27\\python.exe C:\\Users\\Bens\\Desktop\\test.py");
 builder.redirectErrorStream(true);
 Process p = builder.start();
 BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
 String line;
 while (true) {
 line = r.readLine();
 if (line == null) {
 break;
 }
 System.out.println(line);
 }
 } catch (IOException ex) {
 Logger.getLogger(TCPServer.class.getName()).log(Level.SEVERE, null, ex);
 }

• Piyush Shrivastava: Hey can you guide me on how to do this on Linux?
• BEN SEBASTIAN: you can use String[] commands = new String[]{"/bin/sh", "-c", command}; ProcessBuilder builder = new ProcessBuilder(commands ); if in the case of debian you can try "/bin/bash" instead of "/bin/sh"