📅  最后修改于: 2022-03-11 14:52:04.964000             🧑  作者: Mango
String str = "itiswhatitis";
//returns the index of the first i in "is"
str.indexOf("is");
//returns the index of the second occurence of i in "is" after the first
str.indexOf("is", str.indexOf("is") + 1);