code: public static String matcherFound(Matcher m) {
          StringBuilder sb = new StringBuilder();
          sb.append(String.format("%d/%d  Regin:%d/%d\n",
                                  m.start(),
                                  m.end(),
                                  m.regionStart(),
                                  m.regionEnd()));
          for (int i = 0; i <= m.groupCount(); i++)
              sb.append(String.format("%2d:[%3d,%3d) %s\n", i, m.start(i), m.end(i), m.group(i)));
          return sb.toString();
      }
docs: 显示 Matcher 的详细信息
  
  @param m
  Matcher 对象，必须执行过 find
  @return 信息