Java 中的 Matcher groupCount() 方法(带示例)


java.util.regex.Matcher 类表示执行各种匹配操作的引擎。此类没有构造函数,你可以使用 java.util.regex.Pattern 类的 matches() 方法创建/获取此类的对象。

这个 (Matcher) 类的方法 groupCount() 计算当前匹配中的捕获组的数量。

示例 1

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class GroupTest {
   public static void main(String[] args) {
      String regex = "(.*)(\d+)(.*)";
      String input = "This is a sample Text, 1234, with numbers in between.";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Matching the compiled pattern in the String
      Matcher matcher = pattern.matcher(input);
      if(matcher.find()) {
         System.out.println("First group match: "+matcher.group(1));
         System.out.println("Second group match: "+matcher.group(2));
         System.out.println("Third group match: "+matcher.group(3));
         System.out.println("Number of groups capturing: "+matcher.groupCount());
      }
   }
}

输出

First group match: This is a sample Text, 123
Second group match: 4
Third group match: , with numbers in between.
Number of groups: 3

示例 2

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
   public static void main(String[] args) {
      String str1 = "<p>This <b>is</b> an <b>example</b>HTML <b>script</b> where <b>ever</b> alternative <b>word</b> is <b>bold</b></p>.";
      //Regular expression to match contents of the bold tags
      String regex = "(t(\S+)t)(\s)";
      String str = "the words tit tat tweet tostff tact that tilt text start and end wit the letter t ";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Matching the compiled pattern in the String
      Matcher matcher = pattern.matcher(str);
      while (matcher.find()) {
         System.out.println(matcher.group(0));
      }
      System.out.println("Total capturing groups: "+matcher.groupCount());
   }
}

输出

tit
tat
tweet
tact
that
tilt
text
tart
Total capturing groups: 3

更新于: 2019 年 11 月 20 日

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