Whoops! Lost connection to undefined - Connection Lost Just After The Connection Established

Greenhorn

Posts: 1

posted 9 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

For Last couple of days i have been trying spring 4 websocket .I am using apache-tomcat-8 and this is not a maven project. But There is a problem.
Here are my snippets

index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
    <%@ taglib uri="http://www.springframework.org/tags" prefix="spring" %>
    <%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
        <title>Hello WebSocket</title>
        <script type="text/javascript" src="./js/sockjs-0.3.4.js"></script>
        <script type="text/javascript" src="./js/stomp.js"></script>
        <script type="text/javascript">
            var stompClient = null;
    
            function setConnected(connected) {
                document.getElementById('connect').disabled = connected;
                document.getElementById('disconnect').disabled = !connected;
                document.getElementById('conversationDiv').style.visibility = connected ? 'visible' : 'hidden';
                document.getElementById('response').innerHTML = '';
            }
    
            function connect() {
            	
            	 var socket = new SockJS("<c:url value='/hello'/>");
                stompClient = Stomp.over(socket);
                stompClient.connect({}, function(frame) {
                    setConnected(true);
                    console.log('Connected: ' + frame);
                    window.alert('Connected: ' + frame);
                    stompClient.subscribe('/topic/greetings', function(greeting){
                        showGreeting(JSON.parse(greeting.body).content);
                    });
                });
            }
    
            function disconnect() {
                if (stompClient != null) {
                    stompClient.disconnect();
                }
                setConnected(false);
                console.log("Disconnected");
            }
    
            function sendName() {
                var name = document.getElementById('name').value;
                stompClient.send("/app/hello", {}, JSON.stringify({ 'name': name }));
            }
    
            function showGreeting(message) {
                var response = document.getElementById('response');
                var p = document.createElement('p');
                p.style.wordWrap = 'break-word';
                p.appendChild(document.createTextNode(message));
                response.appendChild(p);
            }
        </script>
    </head>
    <body>
    <noscript><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websocket relies on Javascript being enabled. Please enable
        Javascript and reload this page!</h2></noscript>
    <div>
        <div>
            <button id="connect" onclick='connect();'>Connect</button>
            <button id="disconnect" disabled="disabled" onclick="disconnect();">Disconnect</button>
        </div>
        <div id="conversationDiv">
            <label>What is your name?</label><input type="text" id="name" />
            <button id="sendName" onclick="sendName();">Send</button>
            <p id="response"></p>
        </div>
    </div>
    </body>
    </html>

WebSocketConfig.xml

HelloMessage.java

Greeting.java

GreetingController.java

web.xml

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xmlns="http://java.sun.com/xml/ns/javaee"
             xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
             xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
             id="WebApp_ID"
             version="3.0">
      <display-name>CRUDWebAppMavenized</display-name>
      
       <listener>
    	    <listener-class>
    	        org.springframework.web.context.ContextLoaderListener
    	    </listener-class>
    	</listener>
    	
       <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value> /WEB-INF/WebSocketConfig.xml</param-value>
        
    </context-param>
    
    	<servlet>
    		<servlet-name>spring</servlet-name>
    		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    		<load-on-startup>1</load-on-startup>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>spring</servlet-name>
    		<url-pattern>/</url-pattern>
    	</servlet-mapping>
    	    	
      <welcome-file-list>
        
        <welcome-file>index.jsp</welcome-file>
        
      </welcome-file-list>
    </web-app>

spring-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:p="http://www.springframework.org/schema/p"
           xmlns:jee="http://www.springframework.org/schema/jee"
           xmlns:aop="http://www.springframework.org/schema/aop"
           xmlns:tx="http://www.springframework.org/schema/tx"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:util="http://www.springframework.org/schema/util"
           xmlns:mvc="http://www.springframework.org/schema/mvc"
           xsi:schemaLocation="
                http://www.springframework.org/schema/beans     http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                http://www.springframework.org/schema/context   http://www.springframework.org/schema/context/spring-context-3.0.xsd
                http://www.springframework.org/schema/jee       http://www.springframework.org/schema/jee/spring-jee.xsd
                http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
                http://www.springframework.org/schema/aop       http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
                http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd
                http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
    
    	<mvc:annotation-driven/>
        <mvc:default-servlet-handler/>
    	
    	<context:annotation-config />
    	
    	<context:component-scan base-package="com.springws.test" />	
    	
    	<bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
    	    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
    	    <property name="prefix" value="/"/>
    	    <property name="suffix" value=".jsp"/>
    	</bean>
    	<tx:annotation-driven />
    	
    </beans>

WebSocketConfig.java

package com.springws.test;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.messaging.simp.config.MessageBrokerRegistry;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.servlet.config.annotation.EnableWebMvc;
    import org.springframework.web.socket.config.annotation.AbstractWebSocketMessageBrokerConfigurer;
    import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
    import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
    
    @Configuration
    @ComponentScan(basePackages = {"com.springws.test"})
    @EnableWebSocketMessageBroker
    @EnableWebMvc
    @Controller
    public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
    
    	@Override
    	public void configureMessageBroker(MessageBrokerRegistry config) {
    		config.enableSimpleBroker("/topic");
    		config.setApplicationDestinationPrefixes("/app");
    	}
    
    	@Override
    	public void registerStompEndpoints(StompEndpointRegistry registry) {
    		registry.addEndpoint("/hello").withSockJS();
    	}
    	    
    }

But in browser console its giving the following output

why its losing connection ?

Libraries.jpg

Arun Kumarr

Ranch Hand

Posts: 662

I like...

posted 9 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

I'm no web socket expert.
But I tried googling and found this. May be this will help solve your issue.
Also check the accepted answer here.

If you are not laughing at yourself, then you just didn't get the joke.

Rickson Menezes

Greenhorn

Posts: 1

posted 5 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

It's because of the issue of /info=34424 - with 404 error...whoops lost connections - that I had to abandon using the xml approach suggested at other places. I have Spring 4.2 in my project and many SockJS Stomp implementations usually work well with Spring Boot implementations. This implementation from Baeldung worked(for me without changing from Spring 4.2 to 5). After Using the dependencies mentioned in his blog, it still gave me ClassNotFoundError. I added the below dependency to fix it.

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.2.3.RELEASE</version>
</dependency>

Thank you my well lotioned goddess! Here, have my favorite tiny ad!

We need your help - Coderanch server fundraiser

https://coderanch.com/wiki/782867/Coderanch-server-fundraiser