Benchmark

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;


public class Test {
    private static class PathReader {
        private String inputString;
        private int currentPosition = 0;
        private int length = 0;

        public PathReader(String string) {
            inputString = string;
            length = inputString.length();

            currentPosition = 0;
        }

        public boolean hasNext() {
            skipSpaces();
            return currentPosition < length;
        }

        public char getNext() {
            return inputString.charAt(currentPosition++);
        }

        public char peekNext() {
            return inputString.charAt(currentPosition);
        }

        private void skipCharacter() {
            currentPosition++;
        }

        private void skipSpaces() {
            while (currentPosition < length) {
                char c = peekNext();

                switch (c) {
                    case ' ':
                    case ',':
                    case '\n':
                    case '\t':
                    case '\r':
                        break;

                    default:
                        return;
                }

                skipCharacter();
            }
        }

        public float parseFloat() {
            boolean exp = false;

            int j = currentPosition;

            if (inputString.charAt(j) == '-') {
                getNext();
            }

            while (currentPosition < length) {
                char c = getNext();

                switch (c) {
                    case '0':
                    case '1':
                    case '2':
                    case '3':
                    case '4':
                    case '5':
                    case '6':
                    case '7':
                    case '8':
                    case '9':
                    case '+':
                    case '.':
                        exp = false;
                        break;

                    case '-':
                        if (exp) {
                            exp = false;
                        } else {
                            currentPosition--;
                            return Float.parseFloat(inputString.substring(j, currentPosition));
                        }
                        break;

                    case 'e':
                    case 'E':
                        exp = true;
                        break;

                    default:
                        currentPosition--;
                        return Float.parseFloat(inputString.substring(j, currentPosition));
                }
            }

            return Float.parseFloat(inputString.substring(j, currentPosition));
        }
    }

    public static void main(String[] args) throws IOException {
        String data = new String(Files.readAllBytes(Paths.get("test.txt")), StandardCharsets.UTF_8);

        // TEST 1
        long time = System.nanoTime();

        for( int i = 1; i < 1000; i++ ){
            PathReader reader = new PathReader(data);
            while(reader.hasNext()){ reader.parseFloat(); }
        }

        time = System.nanoTime() - time;

        System.out.println("Using reader: " + time);

        // TEST 2
        time = System.nanoTime();

        for( int i = 1; i < 1000; i++ ){
            data.replaceAll("[^\\d.-]|(?=-)", " ").trim().split(" +");
        }

        time = System.nanoTime() - time;

        System.out.println("Using regexp: " + time);
    }
}