Question

I want to execute an operating system command in Java, and then print out it’s returned value. Like this:

This is what I am trying…

String location_of_my_exe_and_some_parameters = "c:\\blabla.exe /hello -hi";
Runtime.getRuntime().exec(location_of_my_exe_and_some_parameters);

I tried putting a System.out.print() on the beginning of my Runtime… line, but it failed. Because, apparently, getRuntime() returns a Runtime object.

Now, the problem is, when I execute the “blabla.exe /hello -hi” command in command line, I got a result like: “You executed some command, hurray!”. But, in Java, I got nothing.

I tried putting the return value into a Runtime object, to an Object object. However, they both failed. How can I accomplish this?

Problem Solved – this is my solution

Process process = new ProcessBuilder(location, args).start();
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;

while ((line = br.readLine()) != null) {
    System.out.println(line);
}

Answer 1

Notice that Runtime.exec(...) returns a Process object. You can use this object to capture its input stream and retrieve whatever it prints to the standard output:

Process p = Runtime.getRuntime().exec(location_of_my_exe_and_some_parameters);
InputStream is = p.getInputStream();

// read process output from is