Java判斷1個字符串中出現了幾次其他字符串

public class Test {
        public static int count(String text,String sub){
            int count =0, start =0;
            while((start=text.indexOf(sub,start))>=0){
                start += sub.length();
                count ++;
            }
            return count;
        }
        public static void main(String[] args){
            String text ="nihaoksdoksad";
            String sub ="o k";
            System.out.println(count(text,sub));
        }
    }