Java中的Matcher group()方法与示例
java.util.regex.Matcher类表示执行各种匹配操作的引擎。该类没有构造函数，可以使用matches()类java.util.regex.Pattern的方法创建/获取该类的对象。
这个(Matcher)类的group()方法在上一次匹配期间返回匹配的输入子序列。
例子1
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class GroupExample {
public static void main(String[] args) {
String str = "<p>This <b>is</b> an <b>example</b> HTML <b>script</b> "
+ "where <b>every</b> alternative <b>word</b> is <b>bold</b>. "
+ "It <i>also</i> contains <i>italic</i> words</p>";
//正则表达式以匹配粗体标签的内容
String regex = "<b>(\\S+)</b>|<i>(\\S+)</i>";
//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());
}
}
}输出结果
<b>is</b> <b>example</b> <b>script</b> <b>every</b> <b>word</b> <b>bold</b> <i>also</i> <i>italic</i>
此方法的另一个变体接受表示组的整数变量，其中捕获的组从1（从左到右）开始索引。
例子2
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.";
//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("match: "+matcher.group(0));
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));
}
}
}输出结果
match: This is a sample Text, 1234, with numbers in between. First group match: This is a sample Text, 123 Second group match: 4 Third group match: , with numbers in between.