Schlagwort: Sping Framework

How to count occurrences of a character in a String with Java?

Code sample:

public class CharacterCounter
{
  public static int countOccurrences(String find, String string)
  {
    int count = 0;
    int indexOf = 0;
 
    while (indexOf > -1)
    {
      indexOf = string.indexOf(find, indexOf + 1);
      if (indexOf > -1)
        count++;
    }
 
    return count;
  }
}

Method call:

int occurrences = CharacterCounter.countOccurrences("l", "Hello World.");
System.out.println(occurrences); // 3

You can also count the occurrences of characters in a string by using the Apache commons lang library with the following one-liner:

int count = StringUtils.countMatches("a.b.c.d", ".");

If you are using the Sping Framework then you can do:

int occurance = StringUtils.countOccurrencesOf("a.b.c.d", ".");

If you want to be really smart (and don’t want to use a loop), then you can also use this one here:

int count = string.length() - string.replace(find, "").length();