java.time.MatchResult.groupCount()方法

java.time.MatchResult.groupCount()方法返回此匹配结果模式中的捕获组数。

声明

以下是java.time.MatchResult.groupCount()方法的声明。

int groupCount()

返回值

此匹配器模式中的捕获组数。

示例

以下示例显示了java.time.MatchResult.groupCount()方法的用法。

package com.zaixian;

import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MatchResultDemo {
   private static final String REGEX = "(.*)(\\d+)(.*)";
   private static final String INPUT = "This is a sample Text, 1234, with numbers in between.";

   public static void main(String[] args) {
      // create a pattern
      Pattern pattern = Pattern.compile(REGEX);

      // get a matcher object
      Matcher matcher = pattern.matcher(INPUT); 

      if(matcher.find()) {
         //get the MatchResult Object 
         MatchResult result = matcher.toMatchResult();

         //Prints the number of capturing groups in this match result's pattern.
         System.out.println("Capturing Groups: "+result.groupCount());
      }
   }
}

编译并运行上面的程序，这将产生以下结果 -

First Capturing Group - Match String: This is a sample Text, 1234, with numbers in between.