判断网络IP端口是否可连接

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;

public class ConnectionUtils {

    private static final Logger LOGGER = LoggerFactory.getLogger(ConnectionUtils.class);

    private static final int TIMEOUT = 3000;

    public static void main(String[] args) {
        System.out.println(isReachable("192.168.43.103"));
        System.out.println(isConnectable("192.168.43.103", 8081));
    }

    public static boolean isReachable(String ip) {
        if (StringUtils.isBlank(ip)) {
            return false;
        }
        try {
            return InetAddress.getByName(ip).isReachable(TIMEOUT);
        } catch (Exception e) {
            LOGGER.info("isReachable({}) encoutered exception :{}", ip, e);
        }
        return false;
    }

    public static boolean isConnectable(String ip, int port) {
        if (StringUtils.isBlank(ip) || port < 0) {
            return false;
        }
        Socket socket = new Socket();
        InputStream inputStream = null;
        try {
            socket.setSoTimeout(TIMEOUT);
            socket.connect(new InetSocketAddress(ip, port));
            inputStream = socket.getInputStream();
            byte[] b = new byte[1024];
            int size;
            while (true) {
                size = inputStream.read(b);
                if (-1 == size) {
                    break;
                }
            }
        } catch (Exception e) {
            LOGGER.info("isConnectable({},{}) encoutered exception :{}", ip, port, e);
            String message = e.getMessage();
            System.out.println(message);
            if (StringUtils.isNotBlank(message) && (message.lastIndexOf("Connection refused") != -1 || message.lastIndexOf("Connection timed out") != -1)) {
                return false;
            }

        } finally {
            try {
                socket.close();
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (IOException e) {

            }
        }
        return true;
    }
}