code: public static Inet4Address fromIpv4String(String address) {
  		byte[] bytes = ip4StringToBytes(address);
  		if (bytes == null) {
  			return null;
  		} else {
  			try {
  				return (Inet4Address) Inet4Address.getByAddress(bytes);
  			} catch (UnknownHostException e) {
  				throw new AssertionError(e);
  			}
  		}
  	}
docs: 从IPv4String转换为InetAddress.
  
  IpString如果确定ipv4, 使用本方法减少字符分析消耗 .
  
  先字符串传换为byte[]再调getByAddress(byte[])，避免了调用getByName(ip)可能引起的DNS访问.