Problem Description: the websocket project was well deployed before. When it was transplanted to the domain name specified by the government cloud SLB, an error occurred:
error during websocket handshake unexpected response code 404

Solution

1. Configure nginx

In any case, configure nginx:
proxy_http_version 1.1;
proxy_set_header Connection "upgrade";
proxy_set_header Upgrade $http_upgrade;

location /xxx{
    proxy_pass http://127.0.0.1:7071/xxx;
    proxy_redirect    off;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

    proxy_http_version 1.1;
    proxy_set_header Connection "upgrade";
    proxy_set_header Upgrade $http_upgrade;
    
    proxy_connect_timeout 60s;
    proxy_read_timeout 7200s;
    proxy_send_timeout 600s;
    
    # 再不行的话就把下面的设置试一下
    #proxy_set_header Upgrade websocket;
    #proxy_pass_request_headers on;
    #access_log off;
    #proxy_buffering off;
    
}

2. Websocket configuration

We use springboot, and all configurations cannot be less

import com.fh.websocket.session.MySpringConfigurator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * enable WebSocket support
 */
@Configuration
public class WebSocketConfig {

	@Bean
	public ServerEndpointExporter serverEndpointExporter() {
		return new ServerEndpointExporter();
	}

	@Bean
	public MySpringConfigurator mySpringConfigurator() {
		return new MySpringConfigurator();
	}
}

3. Websocketserver needs to add a parameterless constructor

This is a pit, and it is normal to deploy to another
transplanting will not work in the past.