네트워크 예외1 - 연결 예외

import java.io.IOException;
import java.net.ConnectException;
import java.net.Socket;
import java.net.UnknownHostException;

public class ConnectMain {

    public static void main(String[] args) throws IOException {
        unknownHostEx1();
        unknownHostEx2();
        connectionRefused();
    }

    private static void unknownHostEx1() throws IOException {
        try {
            Socket socket = new Socket("999.999.999.999", 80);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }

    private static void unknownHostEx2() throws IOException {
        try {
            Socket socket = new Socket("google.gogo", 80);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }

    private static void connectionRefused() throws IOException {
        try {
            Socket socket = new Socket("localhost", 45678);
        } catch (ConnectException e) {
            e.printStackTrace();
        }
    }
}

 

UnknownHostException : 없는 도메인이거나 존재하지 않는 IP

ConnectException : 연결 실패