几秒钟后，Socket.io Java客户端自动断开连接

Question

I am trying to keep a connection between the server and my java client alive. This is my code:

import io.socket.client.*;
import io.socket.client.IO;
import java.net.URISyntaxException;

public class Main {
    public static void main(String[] args) throws URISyntaxException, InterruptedException {
        IO.Options opts = new IO.Options();
        opts.reconnection = true;
        Socket socket = IO.socket("http://localhost:3000", opts);
        socket.connect();
        socket.on("disconnect", args123 -> System.out.println("disconnect"));
        Thread t = new Thread(new test(socket));
        t.start();
    }
}

class test implements Runnable{
    private Socket socket;
    public test(Socket socket){
        this.socket = socket;
    }
    @Override
    public void run() {
        try {
            Thread.sleep(3000);
            socket.emit("test","test");
            System.out.println("test");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
} 

The test event in the thread does not arrive on the server because my client disconnects automatically.

I also tried this option for my server: {transports: ['websocket'], upgrade: false}

or setting the ping interval and timeout interval

Answer 1

I believe your server is a "http" server. So that, you can keep connection alive, but you have to tell this to the server. This is done by request headers. So, simply, I would send "Connection: keep-alive" header. Moreover, your code doesn't look like an http implementation. So, first you should start implementing "http" protocol, then send "Connection: keep-alive" header.

Trying to keep a connection alive from client is not enough to keep really it alive. You have to agree with server.

Check how you can keep alive a http connection on https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Keep-Alive