code: private static String getJmxResult(MBeanServerConnection connetion, String url) throws Exception {
          ObjectName name = new ObjectName(DruidStatService.MBEAN_NAME);
  
          return (String) conn.invoke(name, "service", new String[]{url},
                  new String[]{String.class.getName()});
      }
docs: 根据指定的url来获取jmx服务返回的内容.
  
  @param connetion jmx连接
  @param url       url内容
  @return the jmx返回的内容
  @throws Exception the exception