从下标 0 开始索引，找出单词 “welcome” 在字符串“Hello, welcome to my world.” 中出现的位置，找不到返回 -1的代码

int index = -1;
String str = "Hello, welcome to my world.";
String keyword = "welcome";
String[] words = str.split(" ");
for (int i = 0; i < words.length; i++) {
if (words[i].equals(keyword)) {
index = i;
break;
}
}
System.out.println(index); // 输出 1