File saving

[slan]

I'm learning Java for about 2-3 weeks and I'm stuck and I'm not sure if I have the car in front of my horses or no:
All the programs I learned from the book (yep that one for dummies) is about posting data on the screen or saving data into a file but the data was already pre-written in the code. I want to my program to take what I write on the keyboard, I will see on the screen and then that will be saved on a file. I want to be able to type a few things before the program ends like:
Name : Luis Barros
Age : 99
State : New Jersey
etc....
Then the program will end when I type exit or quit.
Is that too complicated and I should buy another book -the one for idiots or is normal to be on the pause mode when we are learning??
Thanks in advanced for your answers.

[BigDaddyLH]

I/O, especially console-based I/O can be fiddley. Imagine trying to get the user to enter a number from 0 to 100. You have to try to parse the string entered to make sure it first can parse, that it's "50", not "fifty", and second that it's in range and not -4 or 104. If this fails, you may want to repeat your attempt at input. Tedious.

That being said, getting input from the console window is no harder that getting it from a file. Here is a demo that copies that input to a file.

import java.io.*;
 
public class SaveToFile {
    public static void main(String[] args) throws IOException {
        System.out.println("Enter text. End with a blank line.");
        BufferedReader in = new BufferedReader(
            new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter("temp.txt");
        String line;
        System.out.print(">");
        while ((line = in.readLine()) != null && !line.isEmpty()) {
            out.println(line);
            System.out.print(">");
        }
        out.close();
        in.close();
    }
}

I've never looked at a Dummies book for Java so I can't comment on them. There are other free resources out there you could look at. For example, Sun's tutorials:

http://java.sun.com/docs/books/tutorial/

This site has it's own "howtos" as well:

http://www.thescripts.com/howtos.php#link163

And if you haven't already, always keep a browser tab open to the API:

http://java.sun.com/javase/6/docs/api/

[slan]

I used part of your code and everything works fine..but will not save into a file :-)))
Seeing my code you can tell me what's wrong?
Thanks

import static java.lang.System.out;
import java.util.Scanner;
import java.io.*;
 
class Info {
    public static void main(String args[]) throws IOException {
 
        Scanner myScanner = new Scanner(System.in);
        out.print("Serial Number : ");
        String num = myScanner.next();
        out.print("Model : ");
        String mod = myScanner.next();
        out.print("Parts : ");
        String part = myScanner.next();
        out.print("Press Enter to exit the program ");
        String press = myScanner.next();
 
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter("e:\\java\\data.txt");
 
        while ((press = in.readLine()) != null && !press.isEmpty()) {
            out.println(press);
        }
        out.close();
        in.close();
 
 
    }
}
 
 

[BigDaddyLH]

First, I'm not a fan of static imports. In your code, I'm wondering if you are confusing the two uses of "out" -- one out is System.out, the other is the PrintWriter that writes to the file. Here is your code disambiguated. Do you understand why it does what it does, now?

import java.util.Scanner;
import java.io.*;
 
class Info {
    public static void main(String args[]) throws IOException {
        Scanner myScanner = new Scanner(System.in);
        System.out.print("Serial Number : ");
        String num = myScanner.next();
        System.out.print("Model : ");
        String mod = myScanner.next();
        System.out.print("Parts : ");
        String part = myScanner.next();
        System.out.print("Press Enter to exit the program ");
        String press = myScanner.next();
 
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter fileOut = new PrintWriter("data.txt");
 
        while ((press = in.readLine()) != null && !press.isEmpty()) {
            fileOut.println(press);
        }
        fileOut.close();
        in.close();
    }
}
 

[BigDaddyLH]

Or did you want to do something like this?

import java.util.Scanner;
import java.io.*;
 
class Info {
    public static void main(String args[]) throws IOException {
        Scanner myScanner = new Scanner(System.in);
        System.out.print("Serial Number : ");
        String num = myScanner.next();
        System.out.print("Model : ");
        String mod = myScanner.next();
        System.out.print("Parts : ");
        String part = myScanner.next();
 
        PrintWriter fileOut = new PrintWriter("data.txt");
        fileOut.format("Serial Number : %s%n", num);
        fileOut.format("Model : %s%n", mod);
        fileOut.format("Parts : %s%n", part);
        fileOut.close();
    }
}

Have you studies the I/O tutorial at Sun?
http://java.sun.com/docs/books/tutor.../io/index.html

[slan]

Have you studies the I/O tutorial at Sun?
http://java.sun.com/docs/books/tutor.../io/index.html

That's it, now after you did it looks easy :) I did some of the Sun's tutorial but I was getting obcessed for the fact I couldn't do something like that, everywhere I looked I couldn't find a sample were I could based on it. Now I'm going to do that tutorial, and I bet the answer I was looking will jump in front of my eyes.
Thank you.
Luis Barros