How to parse string with Java?

Question

I am trying to make a simple calculator application that would take a string like this

5 + 4 + 3 - 2 - 10 + 15

I need Java to parse this string into an array

{5, +4, +3, -2, -10, +15}

Assume the user may enter 0 or more spaces between each number and each operator

I'm new to Java so I'm not entirely sure how to accomplish this.

Solution

Based off the input of some of the answers here, I found this to be the best solution

// input
String s = "5 + 4 + 3 - 2 - 10 + 15";
ArrayList<Integer> numbers = new ArrayList<Integer>();

// remove whitespace
s = s.replaceAll("\\s+", "");

// parse string
Pattern pattern = Pattern.compile("[-]?\\d+");
Matcher matcher = pattern.matcher(s);

// add numbers to array
while (matcher.find()) {
  numbers.add(Integer.parseInt(matcher.group()));
}

// numbers
// {5, 4, 3, -2, -10, 15}