Java如何在正则表达式中使用量词？

2024-04-16 11:18:03 319

package org.nhooo.example.regex; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexQuantifierDemo { public static void main(String[] args) { String[] expressions = {"x?", "x*", "x+", "x{2}", "x{2,}", "x{2,5}"}; String input = "xxxxxx yyyxxxxxx zzzxxxxxx"; for (String expression : expressions) { //将给定的正则表达式编译为 //模式并创建一个匹配器 //针对此模式的给定输入。 Pattern pattern = Pattern.compile(expression); Matcher matcher = pattern.matcher(input); //查找每个匹配并打印 System.out.format("regex: %s %n", expression); while (matcher.find()) { System.out.format("Text \"%s\" found at %d to %d%n", matcher.group(), matcher.start(), matcher.end()); } System.out.println("------------------------------"); } } }

regex: x? Text "x" found at 0 to 1 Text "x" found at 1 to 2 Text "x" found at 2 to 3 Text "x" found at 3 to 4 Text "x" found at 4 to 5 Text "x" found at 5 to 6 Text "" found at 6 to 6 Text "" found at 7 to 7 Text "" found at 8 to 8 Text "" found at 9 to 9 Text "x" found at 10 to 11 Text "x" found at 11 to 12 Text "x" found at 12 to 13 Text "x" found at 13 to 14 Text "x" found at 14 to 15 Text "x" found at 15 to 16 Text "" found at 16 to 16 Text "" found at 17 to 17 Text "" found at 18 to 18 Text "" found at 19 to 19 Text "x" found at 20 to 21 Text "x" found at 21 to 22 Text "x" found at 22 to 23 Text "x" found at 23 to 24 Text "x" found at 24 to 25 Text "x" found at 25 to 26 Text "" found at 26 to 26 ------------------------------ regex: x* Text "xxxxxx" found at 0 to 6 Text "" found at 6 to 6 Text "" found at 7 to 7 Text "" found at 8 to 8 Text "" found at 9 to 9 Text "xxxxxx" found at 10 to 16 Text "" found at 16 to 16 Text "" found at 17 to 17 Text "" found at 18 to 18 Text "" found at 19 to 19 Text "xxxxxx" found at 20 to 26 Text "" found at 26 to 26 ------------------------------ regex: x+ Text "xxxxxx" found at 0 to 6 Text "xxxxxx" found at 10 to 16 Text "xxxxxx" found at 20 to 26 ------------------------------ regex: x{2} Text "xx" found at 0 to 2 Text "xx" found at 2 to 4 Text "xx" found at 4 to 6 Text "xx" found at 10 to 12 Text "xx" found at 12 to 14 Text "xx" found at 14 to 16 Text "xx" found at 20 to 22 Text "xx" found at 22 to 24 Text "xx" found at 24 to 26 ------------------------------ regex: x{2,} Text "xxxxxx" found at 0 to 6 Text "xxxxxx" found at 10 to 16 Text "xxxxxx" found at 20 to 26 ------------------------------ regex: x{2,5} Text "xxxxx" found at 0 to 5 Text "xxxxx" found at 10 to 15 Text "xxxxx" found at 20 to 25 ------------------------------

Java如何在正则表达式中使用量词？

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