在一个字符串中查找子字符串出现的次数

https://blog.youkuaiyun.com/qq_39045534/article/details/79097864
https://blog.youkuaiyun.com/P90X_Liyuan/article/details/79573294

    public static void countSubstring(){
        //方法1：遍历法
        String s1="abcdabc";
        String s2="ab";
        int count=0;
        for(int i=0;s1.indexOf(s2)!=-1;i++){
            count++;
            s1=s1.substring(s1.indexOf(s2)+s2.length());
        }
        System.out.println(count); //2

        //方法2：分割法
        s1="abcdabc";
        String[] arr=s1.split(s2);
        int len=arr.length-1;
        if(s1.endsWith(s2)) len++;
        System.out.println(len); //2
    }