java - 字符串中子字符串的出现次数

Question

为什么以下算法对我没有停止？ (str 是我要搜索的字符串，findStr 是我要查找的字符串)

String str = "helloslkhellodjladfjhello";
String findStr = "hello";
int lastIndex = 0;
int count = 0;

while (lastIndex != -1) {
    lastIndex = str.indexOf(findStr,lastIndex);

    if( lastIndex != -1)
        count++;

    lastIndex += findStr.length();
}

System.out.println(count);

Answer 1

如何使用StringUtils.countMatches来自 Apache Commons Lang？

String str = "helloslkhellodjladfjhello";
String findStr = "hello";

System.out.println(StringUtils.countMatches(str, findStr));

输出:

3