Java: How do I read from PrintStream?

Question

I am trying to read(append incoming data into a local String) from a PrintStram in the following code block:

    System.out.println("Starting Login Test Cases...");

    out = new PrintStream(new ByteArrayOutputStream());
            command_feeder = new PipedWriter();
            PipedReader in = new PipedReader(command_feeder);

    main_controller = new Controller(in, out);

    for(int i = 0; i < cases.length; i++)
    {
                command_feeder.write(cases[i]);
    }

main_controller will be writing some strings to its out(PrintStream), then how can I read from this PrintStream assuming I can't change any code in Controller class? Thanks in advance.

If you simply want to know what the Controller is doing, then create it with 'new Controller(in, System.out)' and it will write to the console (standard out) — Andreas Dolk

Andreas Dolk Andreas Dolk · Accepted Answer · 2009-07-30T15:21:08

Simply spoken: you can't. A PrintStream is for outputting, to read data, you need an InputStream (or any subclass).

You already have a ByteArrayOutputStream. Easiest to do is:

// ...

ByteArrayOutputStream baos = new ByteArrayOutputStream();
out = new PrintStream(baos);

// ...

ByteArrayInputStream in = new ByteArrayInputStream(baos.toByteArray());

// use in to read the data

Java: How do I read from PrintStream?

3 Answers