Java:获取String中匹配位置的方法?

问题

String match = "hello";
String text = "0123456789hello0123456789";

int position = getPosition(match, text); // should be 10, is there such a method?

#1 热门回答(225 赞)

执行此操作的方法系列包括:

  • int indexOf(String str)indexOf(String str,int fromIndex)
  • int lastIndexOf(String str)lastIndexOf(String str,int fromIndex)

返回指定子字符串[从指定索引开始向前搜索(或向后)]的第一个(或最后一个)出现的字符串中的索引。

String text = "0123hello9012hello8901hello7890";
String word = "hello";

System.out.println(text.indexOf(word)); // prints "4"
System.out.println(text.lastIndexOf(word)); // prints "22"

// find all occurrences forward
for (int i = -1; (i = text.indexOf(word, i + 1)) != -1; i++) {
    System.out.println(i);
} // prints "4", "13", "22"

// find all occurrences backward
for (int i = text.length(); (i = text.lastIndexOf(word, i - 1)) != -1; i++) {
    System.out.println(i);
} // prints "22", "13", "4"

#2 热门回答(31 赞)

这适用于正则表达式。

String text = "I love you so much";
String wordToFind = "love";
Pattern word = Pattern.compile(wordToFind);
Matcher match = word.matcher(text);

while (match.find()) {
     System.out.println("Found love at index "+ match.start() +" - "+ (match.end()-1));
}

输出:>在指数2 - 5找到'爱'
一般规则:-正则表达式从左向右搜索,一旦使用了匹配字符,就无法重复使用。


#3 热门回答(15 赞)

text.indexOf(match);

见3772673604