Not sure if I understand your question correctly, but provided that you can call the Python executable from the console and just want to capture its output in Java, you can use the exec() method in the Java Runtime class.
Process p = Runtime.getRuntime().exec("python yourapp.py");
You can read up on how to actually read the output from this resource: http://www.devdaily.com/java/edu/pj/pj010016 import java.io.*;
public class JavaRunCommand {
public static void main(String args[]) {
String s = null;
try {
// run the Unix "ps -ef" command
// using the Runtime exec method:
Process p = Runtime.getRuntime().exec("ps -ef");
BufferedReader stdInput = new BufferedReader(new
InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new
InputStreamReader(p.getErrorStream()));
// read the output from the command
System.out.println("Here is the standard output of the command:\n");
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
}
// read any errors from the attempted command
System.out.println("Here is the standard error of the command (if any):\n");
while ((s = stdError.readLine()) != null) {
System.out.println(s);
}
System.exit(0);
}
catch (IOException e) {
System.out.println("exception happened - here's what I know: ");
e.printStackTrace();
System.exit(-1);
}
}
}
There is also an Apache library (the Apache exec project) that can help you with this. You can read more about it here:
http://www.devdaily.com/java/java-exec-processbuilder-process-1
http://commons.apache.org/exec/
Answer from Sevas on Stack OverflowNot sure if I understand your question correctly, but provided that you can call the Python executable from the console and just want to capture its output in Java, you can use the exec() method in the Java Runtime class.
Process p = Runtime.getRuntime().exec("python yourapp.py");
You can read up on how to actually read the output from this resource: http://www.devdaily.com/java/edu/pj/pj010016 import java.io.*;
public class JavaRunCommand {
public static void main(String args[]) {
String s = null;
try {
// run the Unix "ps -ef" command
// using the Runtime exec method:
Process p = Runtime.getRuntime().exec("ps -ef");
BufferedReader stdInput = new BufferedReader(new
InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new
InputStreamReader(p.getErrorStream()));
// read the output from the command
System.out.println("Here is the standard output of the command:\n");
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
}
// read any errors from the attempted command
System.out.println("Here is the standard error of the command (if any):\n");
while ((s = stdError.readLine()) != null) {
System.out.println(s);
}
System.exit(0);
}
catch (IOException e) {
System.out.println("exception happened - here's what I know: ");
e.printStackTrace();
System.exit(-1);
}
}
}
There is also an Apache library (the Apache exec project) that can help you with this. You can read more about it here:
http://www.devdaily.com/java/java-exec-processbuilder-process-1
http://commons.apache.org/exec/
You can include the Jython library in your Java Project. You can download the source code from the Jython project itself.
Jython does offers support for JSR-223 which basically lets you run a Python script from Java.
You can use a ScriptContext to configure where you want to send your output of the execution.
For instance, let's suppose you have the following Python script in a file named numbers.py:
for i in range(1,10):
print(i)
So, you can run it from Java as follows:
public static void main(String[] args) throws ScriptException, IOException {
StringWriter writer = new StringWriter(); //ouput will be stored here
ScriptEngineManager manager = new ScriptEngineManager();
ScriptContext context = new SimpleScriptContext();
context.setWriter(writer); //configures output redirection
ScriptEngine engine = manager.getEngineByName("python");
engine.eval(new FileReader("numbers.py"), context);
System.out.println(writer.toString());
}
And the output will be:
1
2
3
4
5
6
7
8
9
As long as your Python script is compatible with Python 2.5 you will not have any problems running this with Jython.
python - Running a .py file from Java - Stack Overflow
How to start a python process from Java and do IO communication?
How can I call Python from Java?
[Help]How to call Java .class methods in Python
Videos
You can use like this also:
String command = "python /c start python path\to\script\script.py";
Process p = Runtime.getRuntime().exec(command + param );
or
String prg = "import sys";
BufferedWriter out = new BufferedWriter(new FileWriter("path/a.py"));
out.write(prg);
out.close();
Process p = Runtime.getRuntime().exec("python path/a.py");
BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
String ret = in.readLine();
System.out.println("value is : "+ret);
Run Python script from Java
I believe we can use ProcessBuilder
Runtime.getRuntime().exec("python "+cmd + py + ".py");
.....
//since exec has its own process we can use that
ProcessBuilder builder = new ProcessBuilder("python", py + ".py");
builder.directory(new File(cmd));
builder.redirectError();
....
Process newProcess = builder.start();
I'm a python dev, like I know literally no Java. But because I'm experienced in python I can at least kinda understand what I'm doing in Java. But I'm stuck on this. I know it's basic shit, I can do this in python, but I just can't read the language so I can't read any help or guides either.
All I need to do really is start a python program from Java as a subprocess, receive it's output stream and be able to send to its input stream.
The python program is a discord bot using async/await stuff and will run continuously so it needs to be uninterrupted, like if it was run from the terminal EXCEPT the Java program can send input and receive output.
I also suck att processes and stuff (this is on Windows btw) and as I said I suck at Java too so sorry if I gave to little information or something. Just tell me if that's the case.
Thanks in advance :D