How to redirect ProcessBuilder's output to a string?

I am using the following code to start a process builder.I want to know how can I redirect its output to a String.

ProcessBuilder pb = new ProcessBuilder(
    System.getProperty("user.dir") + "/src/generate_list.sh", filename);
Process p = pb.start();

I tried using ByteArrayOutputStream but it didn't seem to work.

Solution 1:

Read from the InputStream. You can append the output to a StringBuilder:

BufferedReader reader = 
                new BufferedReader(new InputStreamReader(process.getInputStream()));
StringBuilder builder = new StringBuilder();
String line = null;
while ( (line = reader.readLine()) != null) {
   builder.append(line);
   builder.append(System.getProperty("line.separator"));
}
String result = builder.toString();

Solution 2:

Using Apache Commons IOUtils you can do it in one line:

ProcessBuilder pb = new ProcessBuilder("pwd");
String output = IOUtils.toString(pb.start().getInputStream(), StandardCharsets.UTF_8);