code: public static String queryIp(String host) {
  		InetAddress[] addresses;
  		try {
  			addresses = InetAddress.getAllByName(host);
  		}
  		catch (UnknownHostException e) {
  			return null;
  		}
  		// System.out.println("len:" + addresses.length);
  		if (addresses.length == 1) {
  			return addresses[0].getHostAddress();
  		}
  		else {
  			// 多IP时，随机返回一个
  			int random = new Random().nextInt(addresses.length);
  			return addresses[random].getHostAddress();
  		}
  	}
docs: 根据域名查询IP，多IP时随机返回1个(查询范围:包括hosts文件、DNS服务器、虚拟DNS).
  
  @param host
  域名
  @return IP