计算某字符串在另一个字符串中出现的次数

public class StrCount {
    
    public static void main(String[] args) {
        int a = Count("aabbdbaaee3f","a");
        System.out.println(a);
    }
    

    public static int Count(String str1,String str2) {
        int index = 0;
        int count = 0;
        while((index = str.indexOf(str2, index)) != -1) {
            count++;
            index = index + str2.length();
        }
        return count;
    }
}