在一个字符串中查找另一个字符串出现的次数

/**    
 *    "In the entire world there‘s nobody like me. 
 *Since the beginning of time, there has never been another person like me. 
 *Nobody has my smile. 
 *Nobody has my eyes, my nose, my hair, my hands, or my voice."
 * 要求:算出my在这段话中出现的次数?
 * 我的思路:
 * 1.寻找一个字符串短语在一段字符串中出现几次,首先肯定是用str.indexOf("my",start)方法
 * 2.indexOf方法的返回值是int,如果找不到就会返回-1
 * 3.利用这一点,可以设定一个循环,并定义一个计数器,
 * 让计算机从段落的起始,一直找到末尾,如果找到一个就计数器+1,直到indexof返回结果为-1时,
 * 停止循环.
 * 4.每一次开始找的位置,是不确定的.每一次的新位置,都是上一次找到"短语的位置"+"短语的长度"
 * 
 * 
 * 
 *
 */
public class IndexDemo {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String str = "In the entire world there‘s nobody like me. "
                + "\nSince the beginning of time, "
                + "there has never been another person like me."
                + "\nNobody has my smile. \nNobody has my eyes, "
                + "my nose, my hair, my hands, or my voice.";
        int count = 0;
        System.out.println("请输入需要查找的单词:");
        String key = scan.next();
        count = serachWord(str,key);
        System.out.println("短语my在段落中出现"+count+"次");
    }


    /**
     * 查找某个单词在段落中出现次数的方法
     * @param str    
     * @return
     */
    /**
     * @param str
     * @param key
     * @return
     */
    public static int serachWord(String str,String key) {
        //记录查找次数
        int count = 0;
        //记录每次查找的下标位置,初始化
        int index = 0;
        //定义循环,如果index的位置不是-1,就一值查找
        while((index = str.indexOf(key,index))!=-1){

            //每循环一次就要明确下一次查找的位置
            index = index+key.length();
            //每查找一次计数器自增
            count ++;
        }
        return count;
    }

}