Simulate value into BufferedReader

[Anjali Lamba]

In Java How do I simulate autowrite to a Buffered reader prompt ?
For example, the BufferedReader says
Enter the name:

here the name Java shouldbe accepted like
Enter the name:Java

through the Java code itself

[Stephan van Hulst]

You could use a pipe. First create a new PipedReader and a PipedWriter like this:

PipedReader pr = new PipedReader();
PipedWriter pw = new PipedWriter(pr);

Now, you can wrap your BufferedReader around the PipedReader. Anything you write in your PipedWriter should appear in your BufferedReader.

[Anjali Lamba]

import java.io.*;
public class New {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		
		String g= "C:\\Program Files\\Beyond\\a.bat";
		Process p = Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + g);
		
//		System.out.print("Enter your name: ");
//		PipedReader pr = new PipedReader();
//		PipedWriter pw = new PipedWriter(pr);
//		BufferedReader br  = new BufferedReader(pr);
//		pw.write("Java\n");
//		String name ="";
//		name = br.readLine();
//		System.out.println(name);
	}
}

I understood your solution(commented in my code above).
Assume running the above program prompts me to give a name in a cmd prompt. Now how do I enter the name through the code?

[Stephan van Hulst]

I don't think you can. The command prompt is just that: it provides a means for a human to provide input. If you want a process to provide input, you can either use a pipe within the same process, or you can redirect standard input to accept input from another process' output.

What is the reason you want to do this? Maybe we can suggest an alternative solution.

[Paul Clapham]

When you have a reference to a Process, you can call its getOutputStream() method to get an OutputStream. What can you do with that? Well:

The API Documentation wrote:Output to the stream is piped into the standard input stream of the process represented by this Process object.

So you can send data to the stdin of the process you ran there, which is what you were asking about.

However in your particular example I don't think that rundll32 is going to be asking for any input. If I'm not mistaken, rundll32 starts up another process which runs whatever you told it to start up, and if I'm also not mistaken, your Java code doesn't have any connection with that process.

[Stephan van Hulst]

Hmm that's pretty cool, I'll have to take a look at that class as well.

[Paul Clapham]

Absolutely. However anybody who wants to use the Process class should read this classic article: When Runtime.exec() won't.