Java app console redirect in C# application?

Ken

Hi. I am trying to open a command window and read/write it from a C# forms app. I have a textbox "textBox1" to display output and "textBox2" for me to type commands to the cmd process. This is the code:

ProcessStartInfo info = new ProcessStartInfo("cmd");
info.UseShellExecute = false;
info.RedirectStandardInput = true;
info.RedirectStandardOutput = true;
info.CreateNoWindow = true;

proc = Process.Start(info);
sw = proc.StandardInput;
string buf = "";
StreamReader sr = proc.StandardOutput;

while (serverrunning) {
buf = sr.ReadLine();
textBox1.Text += buf + Environment.NewLine;
textBox1.SelectionStart = textBox1.Text.Length;
textBox1.ScrollToCaret();
Application.DoEvents();
}

This works for regular DOS stuff. When I run it, I get the "Microsoft Windows [Version 6.1.7600], Copyright" etc etc command prompt header. Only issue is I am not receiving the last line of text until I send a CR, I assume because ReadLine is waiting for that to flush its buffer. I can live with that, but then I launch my java app and that is where the real problem starts.

The java app is a Minecraft server. When you fire it up (java -Xms1G -Xmx1G craftbukkit.jar) regularly I get this:

16:42:46 [INFO] Starting minecraft server version Beta 1.4
16:42:46 [INFO] Loading properties
16:42:46 [INFO] Starting Minecraft server on *:25565
16:42:46 [INFO] This server is running Craftbukkit version git-Bukkit-0.0.0-646-gb61ef8c-b670jnks (M
C: 1.4)
16:42:46 [INFO] Preparing level "world"
16:42:46 [INFO] Preparing start region
16:42:46 [INFO] 144 recipes
16:42:47 [INFO] Preparing spawn area: 89%
16:42:47 [INFO] Done (0.117s)! For help, type "help" or "?[/code]

Problem is, when I run it from my C# linked command process I am seeing this in my textbox:

Microsoft Windows [Version 6.1.7600]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

c:\dropbox\projects\MinecraftManager\bin\Debug>cd\applications\minecraft\server

c:\Applications\Minecraft\Server>java -Xms1G -Xmx1G craftbukkit-0.0.1-SNAPSHOT.jar
>
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>
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I guess java doesn't do stdout right or something. Is there a way around this?

4 Replies

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Sam Hobbs15y ago
Accepted answer
What I would do is to execute the java program in a console window and redirect the IO in the command line. Do you understand what I am saying? Just to determine whether the IO can be redirected. If it does not get redirected then you need to research what others have done to solve the problem. One thing to check is to determine if it is writing to stderr instead of stdout, right?
Sam Hobbs15y ago
I can't think of anything more except try testing redirection in the manner I describe except you can create a file with a line or multiple lines as input to test if redirection works.
Vulpes15y ago
Is it any better if you send:

"stop" + (char)13 + (char)10
Ken15y ago
Ahh, sweet. That was it, I switched to using StandardError and now I get my java output.

Next problem, hehe, is that the java app doesn't accept StandardInput. I sent "stop" + (char)13 to StandardInput and nothing happened, it didn't process it. Is there some other trick for that? this is my sending code that I bound to a KeyPress event on the textbox I type input in:

void textBox2_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e) {
if (e.KeyChar == (char)13) {
    sw.Write(textBox2.Text);
    sw.Flush();
    textBox2.Text = ""; textBox2.Focus();
    e.Handled = true;
    label3.Text = "SENT";
} else {
    if (label3.Text != "") label3.Text = "";
}
}

I've also tried using WriteLine to no avail.