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r/javahelp•
rahulpresentskobe

WebSocket Server Refuses Every Client Attempt to Connect

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Hello everyone, I have just started learning Spring Boot and I was hoping someone here could help me with what feels like a really simple issue. It has taken me days without any real hope yet for fixing whatever this is.

After failing 50+ times to get a basic Java WebSocket Server working on a very old Java EE 7 in Netbeans, I decided to try doing it in Spring Boot, following really simple guides like

https://springhow.com/spring-boot-websocket/

and https://www.javainuse.com/spring/boot-websocket

The javainuse one especially is so straightforward...but still no luck.

I still receive the same error with Spring Boot now, "WebSocket connection to 'ws://localhost:8080/user/' failed", no matter what I do.

It feels like there's an issue with my PC but I've opened the port (yougetsignal verifies), tried turning off firewall, used the public IP vs. localhost, switched endpoints (also tried with "/" and adding an .setAllowedOrigins("*") to my handler function call), enabled WebSockets in "Turn Windows Features on and off", added an inbound firewall rule allowing everything for the port, etc.

I am so lost on what could be wrong, but it can't be the code, right? I've taken these basic projects line for line from these guides but the connection just never gets made.

When I tried connecting through a separate NodeJS project, it returned "Unexpected server response: 200". The server shows this: https://i.imgur.com/nBaxKOq.png

I'm on Windows 10 and don't know what more to try. I thought Spring Boot would be simple enough with all the documentation and help online, but I am out of ideas. Does anyone know what could be wrong?

Edit: I finally figured it out, thank you everyone for trying to help. I did not set up the WebSocketConfig file correctly so it seems like it was never registering the endpoint before. I redid that part, and now it connects and says "Completed 101 SWITCHING_PROTOCOLS". The code was from https://www.javainuse.com/spring/boot-websocket

Posted Oct 16, 2022, 2:08 AM UTC · edited

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1
msx•

What error messages are you reading, both on the browser and on your server?

1
rahulpresentskobeOP•

On the browser there's no error except "connection failed" on console. Is there somewhere else I should look?

The server itself has no errors. I enabled debugging in my application settings though and was able to get this on the server logs https://i.imgur.com/nBaxKOq.png

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dwargo•

A websocket endpoint should return a status 101 to switch protocols - a 200 would indicate the server doesn’t think there’s a websocket at that URL. So you’re connecting fine but the URL is wrong.

In eclipse the project name is usually part of the URL, like was://localhost:8080/com.contoso.project/user/. I don’t know how netbeans does things though.

Try hitting that URL with a browser and see what it says.

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rahulpresentskobeOP•

I tried with my project name, both in browser URL and with the JS but it gave me a 404

1
dwargo•

I think if you press the debug button it will pop up a built-in browser with the correct URL. It’s been like ten years since I switched to Eclipse though, so I’m not positive.

Or you could find the tomcat installation and look at the jar/directory name under the webapps directory. That’s how tomcat actually finds the app, with the exception that a jar named ROOT goes at the root.

I recently switched my projects to maven and it changed the URL from the project name to the artifact ID, but I don’t know if that’s an eclipse thing or a maven thing.

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