Java正则表达式返回参考

import java.util.regex.Matcher;

import java.util.regex.Pattern;





public class Tester {

   public static void main(String[] args) {



      //2 followed by 2 five times

      String test = "222222";





      String pattern = "(\\d\\d\\d\\d\\d)";





      Pattern r = Pattern.compile(pattern);

      Matcher m = r.matcher(test);

      if (m.find( )) {

         System.out.println("Matched!");   

      }else{

          System.out.println("not matched!");    

      }



      //\1 as back reference to capturing group (\d)

      pattern = "(\\d)\\1{5}";





      r = Pattern.compile(pattern);

      m = r.matcher(test);

      if (m.find( )) {

         System.out.println("Matched!");   

      }else{

         System.out.println("not matched!");    

      }

   }

}