how to execute console commands in a java program for node

Question

I need to access the console on the node through java how to make this ?

public class Comando {

public static void main(String[] args) {
    String comando = "C:\\Program Files\\nodejs\\node.exe";  
    try {  
       Process process = Runtime.getRuntime().exec(comando);   
       OutputStream stdin = process.getOutputStream ();
       InputStream stderr = process.getErrorStream ();
       InputStream stdout = process.getInputStream ();


       stdin.write("1+2".getBytes());
       stdin.flush();
    //   System.out.print(stdout.read());
       stdin.close();
       System.out.print(stdout.read());

       //BufferedReader reader = new BufferedReader (new InputStreamReader(stdout));
       //BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(stdin));

      // writer.close();

    } catch (IOException e) {  
        e.printStackTrace();  
    }  
}
}

Answer 1

I expect that node.exe requires text, not binary as you are using it.

This means that using PrintWriter to write lines of text and BufferedReader to read lines of text would make more sense.

Java has a built in Javascript interpreter. I assume you cannot use that for some reason.

Answer 2

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;

public class Comando {

    public static void main(String[] args) {

        String comando = "C:\\Program Files\\nodejs\\node.exe";
        try {

            ProcessBuilder builder = new ProcessBuilder(comando);
            Process process = builder.start();
            OutputStream stdin = process.getOutputStream();
            InputStream stderr = process.getErrorStream();
            InputStream stdout = process.getInputStream();

            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    stdout));
            PrintWriter writer = new PrintWriter(stdin);

            writer.write("1+2");
            writer.flush();
            stdin.close();
            System.out.print(reader.read());// return -1

            // writer.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

It continues at me return -1, when I try read your output