java进程buider无法获得输出

Question

i want to get bat file output real time using java process builder .but the problem is i'm not getting any output .how can i improve this to get output

this is my javacode

void pingIp() throws InterruptedException, IOException {
    Thread t = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                String[] commands = {"C:\\Users\\Madhawa.se\\Desktop\\addonapp\\matrix.bat"};

                ProcessBuilder process = new ProcessBuilder(commands);
                process.redirectErrorStream(true);

                Process shell = process.inheritIO().start();

                //shell.waitFor();
                BufferedReader stdInput = new BufferedReader(new InputStreamReader(shell.getInputStream()));
                BufferedReader stdError = new BufferedReader(new InputStreamReader(shell.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);
                }
            } catch (IOException ex) {
                Logger.getLogger(pingIo.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    });
    t.start();

}

my actual bat file is complex so for example i use following bat file.this bat file print random numbers in intervals[1 s].so i want to get output in my java console in real time

::matrix interval //matrix.bat
@echo off
color 0a
:top
echo %random%%random%%random%%random%
ping 1.1.1.1 -n 1 -w 1000 > nul
goto top

thanks!

Answer 1

inheritIO needs to be used in places where output is not been read through normal means. When used incorrectly it can prevent output from been read from the process.

You should also read the output/error streams in a separate thread and use waitFor AFTER you've started those threads. This allows you to block at that point in the code, but still process the streams, as some processes can stall if the output buffer is not read