public String getServerIp() {          if (serverIp != null) {              return serverIp;          }          // 一个主机有多个网络接口          try {              Enumeration
    
      netInterfaces = NetworkInterface.getNetworkInterfaces();              while (netInterfaces.hasMoreElements()) {                  NetworkInterface netInterface = netInterfaces.nextElement();                  // 每个网络接口,都会有多个"网络地址",比如一定会有lookback地址,会有siteLocal地址等.以及IPV4或者IPV6 .                  Enumeration
     
       addresses = netInterface.getInetAddresses();                  while (addresses.hasMoreElements()) {                      InetAddress address = addresses.nextElement();                      if(address instanceof Inet6Address){                          continue;                      }                      if (address.isSiteLocalAddress() && !address.isLoopbackAddress()) {                          serverIp = address.getHostAddress();                          logger.info("resolve server ip :"+ serverIp);                          continue;                      }                  }              }          } catch (SocketException e) {              e.printStackTrace();          }          return serverIp;      }