Java——递归检查字符串是否回文

public static boolean isPalindromes(String  str){
return isPalindromes(str.toLowerCase().toCharArray(), 0, str.length()-1);
}
private static boolean isPalindromes(char[] charArray, int low, int high){
while(!Character.isLetter(charArray[low]))
low++;
while(!Character.isLetter(charArray[high]))
high--;
if(charArray[low] != charArray[high])       return false;
if(low == high || low == high - 1)      return true;
return isPalindromes(charArray, low+1, high-1);
}