求解啊

求解

循环输出每个java单词的下标，最后一句就是当前下标加上java单词的长度就是过滤掉当前的单词，让下个循环往后读取匹配。

public int indexOf(String str, int fromIndex)Returns the index within this string of the first occurrence of the specified substring, starting at the specified index.
The returned index is the smallest value k for which:
k >= fromIndex && this.startsWith(str, k) If no such value of k exists, then -1 is returned.Parameters:str - the substring to search for.fromIndex - the index from which to start the search.Returns:the index of the first occurrence of the specified substring, starting at the specified index, or -1 if there is no such occurrence.

the index of the first occurrence of the specified substring, starting at the specified index, or -1 if there is no such occurrence.

str - the substring to search for.
fromIndex - the index from which to start the search.

哈哈哈哈，连indexof的方法结构，都没得到，这选毛？

第一圈,index=0, 则从str的0位置搜索与str1第一个匹配的位置, **java刚好是012;

然后,index=str.indexOf(str1, index)=2;
接着 index+=str1.length()==index=index+str1.length=2+4=6;