Running Python scripts in Java

Question

I'm trying to run a python script during the execution of my java code, because it will depend on the output received from the python script. So far I've tried using jythonc, unfortunately to no success, and now im trying to use the java Runtime and java Process to execute the python script.

Now I've run into a problem when trying to call the python script. I feel as though it doesn't even call the script because it takes less than a couple seconds to get to the next page....

Could the problem be how I am calling the python script?? I am trying to run this through a web application...

Here is some of my code:

    String run = "cmd /c python duplicatetestingoriginal.py" ;

    boolean isCreated = fwr.writeFile(BugFile, GD, 500, true, 5, "LET");

    if(isCreated){
        try{
            r = Runtime.getRuntime();
            p = r.exec(run);
            BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
    BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));

    String line = "";
    while ((line = stdInput.readLine()) != null) {
                System.out.println(line);
    }
    while ((line = stdError.readLine()) != null) {
               errorW.write(line);
    }

            int exitVal = p.waitFor();
            arrayList = fwr.readResults();
        }catch(Exception e){

        }
    }
    else{
        // troubleshoot....

    }

Answer 1

Instead of String for the command, split it to chunks and make a String[]. No need to state cmd /c, I think.

This is a sample code from my application:

//Running on windows
command = new String[4];
command[0]=directory.getCanonicalPath()+"/data/ExtenalApp.exe"; //extenal commandline app, not placed in path, but in subfolder
command[1]=directory.getCanonicalPath()+"/data/SomeFile.txt"; //file needed for the external app, sent as an argument
command[2]=arg1; //argument for the app
command[3]=arg2; //argument for the app

//Running on Mac
command = new String[6];
command[0]="python";
command[1]=directory.getCanonicalPath()+"/data/wp.py"; //path to the script
command[2]="-F"; //argument/Flag/option
command[3]="--dir="+path; //argument/option
command[4]="--filename="+filename; //argument/option 
command[5]=argument; //argument/option


Process process = Runtime.getRuntime().exec(command);
process.waitFor();
process.destroy();

I don't handle the Input/Output streams because the script/app doesn't require input, and outputs only when finished, nothing important. Which might not be the case for you.