Ошибка java net connectexception connection refused connect

I’m trying to implement a TCP connection, everything works fine from the server’s side but when I run the client program (from client computer) I get the following error:

java.net.ConnectException: Connection refused
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:432)
        at java.net.Socket.connect(Socket.java:529)
        at java.net.Socket.connect(Socket.java:478)
        at java.net.Socket.<init>(Socket.java:375)
        at java.net.Socket.<init>(Socket.java:189)
        at TCPClient.main(TCPClient.java:13)

I tried changing the socket number in case it was in use but to no avail, does anyone know what is causing this error & how to fix it.

The Server Code:

//TCPServer.java

import java.io.*;
import java.net.*;

class TCPServer {
    public static void main(String argv[]) throws Exception {
        String fromclient;
        String toclient;

        ServerSocket Server = new ServerSocket(5000);

        System.out.println("TCPServer Waiting for client on port 5000");

        while (true) {
            Socket connected = Server.accept();
            System.out.println(" THE CLIENT" + " " + connected.getInetAddress()
                    + ":" + connected.getPort() + " IS CONNECTED ");

            BufferedReader inFromUser = new BufferedReader(
                    new InputStreamReader(System.in));

            BufferedReader inFromClient = new BufferedReader(
                    new InputStreamReader(connected.getInputStream()));

            PrintWriter outToClient = new PrintWriter(
                    connected.getOutputStream(), true);

            while (true) {

                System.out.println("SEND(Type Q or q to Quit):");
                toclient = inFromUser.readLine();

                if (toclient.equals("q") || toclient.equals("Q")) {
                    outToClient.println(toclient);
                    connected.close();
                    break;
                } else {
                    outToClient.println(toclient);
                }

                fromclient = inFromClient.readLine();

                if (fromclient.equals("q") || fromclient.equals("Q")) {
                    connected.close();
                    break;
                } else {
                    System.out.println("RECIEVED:" + fromclient);
                }

            }

        }
    }
}

The Client Code:

//TCPClient.java

import java.io.*;
import java.net.*;

class TCPClient {
    public static void main(String argv[]) throws Exception {
        String FromServer;
        String ToServer;

        Socket clientSocket = new Socket("localhost", 5000);

        BufferedReader inFromUser = new BufferedReader(new InputStreamReader(
                System.in));

        PrintWriter outToServer = new PrintWriter(
                clientSocket.getOutputStream(), true);

        BufferedReader inFromServer = new BufferedReader(new InputStreamReader(
                clientSocket.getInputStream()));

        while (true) {

            FromServer = inFromServer.readLine();

            if (FromServer.equals("q") || FromServer.equals("Q")) {
                clientSocket.close();
                break;
            } else {
                System.out.println("RECIEVED:" + FromServer);
                System.out.println("SEND(Type Q or q to Quit):");

                ToServer = inFromUser.readLine();

                if (ToServer.equals("Q") || ToServer.equals("q")) {
                    outToServer.println(ToServer);
                    clientSocket.close();
                    break;
                } else {
                    outToServer.println(ToServer);
                }
            }
        }
    }
}

I had the same problem, but running the Server before running the Client fixed it.

Hope my experience may be useful to someone. I faced the problem with the same exception stack trace and I couldn’t understand what the issue was. The Database server which I was trying to connect was running and the port was open and was accepting connections.

The issue was with internet connection. The internet connection that I was using was not allowed to connect to the corresponding server. When I changed the connection details, the issue got resolved.

answered Nov 17, 2014 at 12:01

answered Dec 21, 2016 at 18:20

answered Aug 23, 2017 at 13:42

i got this error because I closed ServerSocket inside a for loop that try to accept number of clients inside it (I did not finished accepting all clints)

so be careful where to close your Socket

answered Nov 23, 2019 at 9:51

answered Aug 10, 2020 at 16:21

Change local host to your ip address

 localhost
 //to you local ip
 192.168.xxxx

answered Apr 28, 2021 at 10:46

I saw the same error message «»java.net.ConnectException: Connection refused» in SQuirreLSQL when it was trying to connect to a postgresql database through an ssh tunnel.

Example of opening tunel:

Example of error in Squirrel with Postgresql:

It was trying to connect to the wrong port. After entering the correct port, the process execution was successful.

See more options to fix this error at: https://stackoverflow.com/a/6876306/5857023

answered Jan 6, 2022 at 19:57

answered Aug 12, 2022 at 15:07

For those who are experiencing the same problem and use Spring framework, I would suggest to check an http connection provider configuration. I mean RestTemplate, WebClient, etc.

In my case there was a problem with configured RestTemplate (it’s just an example):

public RestTemplate localRestTemplate() {
   Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("localhost", <some port>));
   SimpleClientHttpRequestFactory clientHttpReq = new SimpleClientHttpRequestFactory();
   clientHttpReq.setProxy(proxy);
   return new RestTemplate(clientHttpReq);
}

I just simplified configuration to:

public RestTemplate restTemplate() {
   return new RestTemplate(new SimpleClientHttpRequestFactory());
}

And it started to work properly.

answered Jan 24 at 17:45

There is a service called MySQL80 that should be running to connect to the database

for windows you can access it by searching for services than look for MySQL80 service and make sure it is running

answered Jul 16, 2021 at 19:50

It could be that there is a previous instance of the client still running and listening on port 5000.