Input/Output of files

Question

Hello,
I am new to Java, and have just recently started learning it. I am student working with a math prof, and I need help with a program that would help our research.
First of all, is it possilbe to input numbers from a textfile which just contains numbers like so:
1
2
3
4
5
6
Into an 2x3 array, like [1 2 3]
[4 5 6]
Could someone help me with the code? Once I have these saved into an array then I am able (with my limited Java knowledge) to do what I need to do with the arrays, it is just a question of transfering the numbers in the first place.
Thanks to anyone who could help, as you'd save me a great deal of time.
Mike Lukas

Answer 1

You will want to look at java.io.FileInputStream. Your input logic will resemble something like the following:
public List getNumbers(final String fileUri)
   throws IOException {
   FileInputStream fileIn = null;
   try {
       List values = new ArrayList();
       fileIn = new FileInputStream(fileUri);
       BufferedReader reader = new BufferedReader(new InputStreamReader(fileIn));
       String line = reader.readLine();
       while (line != null) {
            values.add(Integer.valueOf(line));
            line = reader.readLine();
   finally {
       if (fileIn != null) {
           fileIn.close();
}See the Javadocs for java.util.List for how collections work. Or go to the Collections tutorial on this site.
- Saish