Parsing file filled with integers fast (?)

Question

Hi,
I am trying to parse a file that has a bunch of integers seperated by spaces. I am using a BufferedReader, then looking at each char to see if it's a digit, then getting the digit and computing the integer. This seems to be 10 times slower than the same parser written in C++.
How can I boost the performance?
Thanks!
M.

Answer 1

So I use a LineNumberReader to read one line at the time. I pass that string to getIntegers (see below). This returns a list of integers.
Dealing with bytes directly sounds great. How do I do that?
Thanks!
M.
public ArrayList<Integer> getIntegers(String line){
     line += " ";
     ArrayList<Integer> res = new ArrayList<Integer>();
     boolean start = false;
     boolean neg = false;
     int l = 0;
     char c;
     for(int i = 0; i< line.length(); i++){
          c = line.charAt(i);
          if (c == '-'){
               neg = true;
          } else if (! Character.isWhitespace(c)) {
               if (start == false) start = true;
               l = l * 10 + Character.digit(c, 10);
          } else if (start == true) {
               if (neg) l = -l;
               res.add(new Integer(l));
               l = 0;
               start = false;
               neg = false;
     return res;
}