cdm/src/main/java/ucar/unidata/util/StringUtil2.java
static public int match(String s1, String s2) {
    int i = 0;
    while ((i < s1.length()) && (i < s2.length())) {
      if (s1.charAt(i) != s2.charAt(i)) {
        break;
      }
      i++;
    }
    return i;
  }
static public int match(String s1, String s2) {
    int i = 0;
    while ((i < s1.length()) && (i < s2.length())) {
      if (s1.charAt(i) != s2.charAt(i)) {
        break;
      }
      i++;
    }
    return i;
  }
Count number of chars that match in two strings, starting from front.

@param s1 compare this string
@param s2 compare this string
@return number of matching chars, starting from first char