File Java Tutorial

Scanner defines where a token starts and ends based on a set of delimiters.
The default delimiters are the whitespace characters.
To Change the delimiters
Scanner: useDelimiter(String pattern)
Scanner: useDelimiter(Pattern pattern)
Pattern is a regular expression that specifies the delimiter set.
Use Scanner to compute the average of a list of comma-separated values.

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
public class MainClass {
  public static void main(String args[]) throws IOException {
    FileWriter fout = new FileWriter("test.txt");
    fout.write("2, 3.4,    5,6, 7.4, 9.1, 10.5, done");
    fout.close();
    FileReader fin = new FileReader("Test.txt");
    Scanner src = new Scanner(fin);
    // Set delimiters to space and comma.
    // ", *" tells Scanner to match a comma and zero or more spaces as
    // delimiters.
    src.useDelimiter(", *");
    // Read and sum numbers.
    while (src.hasNext()) {
      if (src.hasNextDouble()) {
        System.out.println(src.nextDouble());
      } else {
        break;
      }
    }
    fin.close();
  }
}
2.0
3.4
5.0
6.0
7.4
9.1
10.5