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，可以使用matches()类java.util.regex.Pattern的方法创建/获取此类的对象。
这个(Matcher)类的groupCount()方法计算当前匹配项中的捕获组数。
例子1import 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.";
//创建一个模式对象
Pattern pattern = Pattern.compile(regex);
//匹配字符串中的已编译模式
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());
}
}
}
输出结果First group match: This is a sample Text, 123
Second group match: 4
Third group match: , with numbers in between.
Number of groups: 3
例子2import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
public static void main(String[] args) {
String str1 = "
This is an exampleHTML script where ever alternative word is bold
.";//正则表达式匹配粗体标签的内容
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 ";
//创建一个模式对象
Pattern pattern = Pattern.compile(regex);
//匹配字符串中的已编译模式
Matcher matcher = pattern.matcher(str);
while (matcher.find()) {
System.out.println(matcher.group(0));
}
System.out.println("Total capturing groups: "+matcher.groupCount());
}
}
输出结果tit
tat
tweet
tact
that
tilt
text
tart
Total capturing groups: 3