Can't write to file

[Peter Ariyibi]

The code below compiles ok but when i run it nothing happens - i want to be able to write whatever i type (system.in) to a file called fromkeyboard. Any thoughts on why this is would be appreciated

import java.io.*;
import java.util.*;

public class TestProperties{
	static String s;
	public static void main (String args[]) throws IOException{
		
		File myFile = new File("fromkeyboard.txt");
		
		InputStreamReader ir = new InputStreamReader (System.in);
		
		try{
		BufferedReader in = new BufferedReader(ir);
		FileWriter wr = new FileWriter(myFile);
		PrintWriter out = new PrintWriter(wr);
	
		while(s != null){	
			s = in.readLine();
			out.println(s);
		}
		}catch (IOException e){}
		out.close();
		in.close();
		
	}
}

[Lester Burnham]

A little hint: Since nothing is assigned to "s", it is null before it reaches the while loop...

[Peter Ariyibi]

thanks.. i have initialised s before the while loop and that seemed to have solved the problem. I then noticed that my out.close and in.close method calls were outside the try block which i have corrected. Although the code works (i can type gibberish and i assume it is written to file), when i check the fromkeyboard file it is empty! Any hints on why the keyboard input is not being written to file?

[Paul Clapham]

Your code might be subject to exceptions. But you would never know, for two reasons:

Your catch block ignores them

You are using a PrintWriter, which ignores exceptions

You can fix the first problem like this:

} catch (IOException e) {
  e.printStackTrace();
}

And you can fix the second problem by using a BufferedWriter rather than a PrintWriter.

[Jesper de Jong]

Welcome to JavaRanch.

Please UseCodeTags when you post source code, that makes the code much easier to read. Being a moderator, I added the code tags to your post above for you.

[Paul Clapham]

Peter Ariyibi wrote:I then noticed that my out.close and in.close method calls were outside the try block which i have corrected.

So now you are asking a question about code which we haven't seen yet...

[Joanne Neal]

Peter Ariyibi wrote:thanks.. i have initialised s before the while loop and that seemed to have solved the problem.

Rather than initialising s to some random value before the loop, you will find that this sort of loop is often written like this

String s;
while((s = in.readLine()) != null) {      
    out.println(s);   
}