Java中输出正则表达式匹配到的内容

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

public class A {
    public static void main(String[] args) {
        String reg = "2[0-9]{11}-{0,1}[0-9]{0,1}";
        Pattern p = Pattern.compile(reg);
        String str = "200000000000-2200000000000";
        Matcher m =p.matcher(str);
        while(m.find())
            System.out.println(m.group(0));
            
    }
}