话不多说, 直接上干货...

public class NetUtils {
    private static final Logger log = LoggerFactory.getLogger(NetUtils.class);

    /**
     * 特别注意: ping不通, 并不代表telnet或者socket就不能正常连接
     * 原因: 协议不同
     * - ping是基于ICMP协议, ping不通可能原因是防火墙或其他主机设置禁用了ICMP协议
     * - telnet/socket都是基于TCP/IP协议簇
     */

    /**
     * 检测ip是否可连接
     * @param host 域名或ip地址
     * @return
     */
    public static NetConnect testIpConnect(String host) {
        boolean reachable = false;
        String msg;

        try {
            InetAddress address = InetAddress.getByName(host);
            // 5000ms timeout
            // 这个方法会尝试发送一个ICMP（Internet Control Message Protocol）回显请求包, ping命令也是基于ICMP协议
            reachable = address.isReachable(5000);
            if (reachable) {
                msg = String.format("Ping %s  : Success", host);
            }else {
                msg = String.format("Ping %s  : Failed", host);
            }
        } catch (UnknownHostException e) {
            msg = String.format("Invalid URL or Host not found: %s", host);
        } catch (Exception e) {
            msg = String.format("Error: %s", e.getMessage());
        }

        log.info(msg);
        return NetConnect.builder().connect(reachable).msg(msg).receiveTime(LocalDateTime.now()).build();
    }

    /**
     * 检测socket是否可连接
     * @param host 域名或ip地址
     * @param port 端口号
     * @return
     */
    public static NetConnect testSocketConnect(String host, int port) {
        boolean reachable = false;
        String msg;

        try {
            //这里创建的是tcp连接的socket, 这里能连接的话, 则http接口应该也可以正常连接
            Socket socket = new Socket();
            // 5000ms timeout
            socket.connect(new InetSocketAddress(host, port), 5000);
            reachable = true;
            msg = String.format("Port %s is open on %s", port, host);
            // 关闭socket连接
            socket.close();
        } catch (Exception e) {
            msg = String.format("Port %s is closed on %s", port, host);
        }

        log.info(msg);
        return NetConnect.builder().connect(reachable).msg(msg).receiveTime(LocalDateTime.now()).build();
    }
}