WAR Deployment (Tomcat, GlassFish, Payara, WildFly)

Prerequisites

1. Create the Project

<project>
 <groupId>com.example</groupId>
 <artifactId>my-chat</artifactId>
 <packaging>war</packaging>
 <dependencies>
 <dependency>
 <groupId>org.atmosphere</groupId>
 <artifactId>atmosphere-runtime</artifactId>
 <version>4.0.0</version>
 </dependency>
 <dependency>
 <groupId>jakarta.inject</groupId>
 <artifactId>jakarta.inject-api</artifactId>
 <version>2.0.1</version>
 </dependency>
 <dependency>
 <groupId>com.fasterxml.jackson.core</groupId>
 <artifactId>jackson-databind</artifactId>
 <version>2.18.2</version>
 </dependency>
 </dependencies>
</project>

2. Configure web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee
 https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd"
 version="6.0">
 <servlet>
 <servlet-name>AtmosphereServlet</servlet-name>
 <servlet-class>org.atmosphere.cpr.AtmosphereServlet</servlet-class>
 <!-- Scan this package for @ManagedService and other annotations -->
 <init-param>
 <param-name>org.atmosphere.cpr.packages</param-name>
 <param-value>com.example.chat</param-value>
 </init-param>
 <!-- Optional: heartbeat frequency -->
 <init-param>
 <param-name>org.atmosphere.interceptor.HeartbeatInterceptor.clientHeartbeatFrequencyInSeconds</param-name>
 <param-value>10</param-value>
 </init-param>
 <load-on-startup>0</load-on-startup>
 <async-supported>true</async-supported>
 </servlet>
 <servlet-mapping>
 <servlet-name>AtmosphereServlet</servlet-name>
 <url-pattern>/chat/*</url-pattern>
 </servlet-mapping>
</web-app>

3. Create the Chat Service

package com.example.chat;
@ManagedService(path = "/chat",
 atmosphereConfig = "org.atmosphere.cpr.maxInactiveActivity=120000")
public class Chat {
 @Inject
 private AtmosphereResource r;
 @Inject
 private AtmosphereResourceEvent event;
 @Ready
 public void onReady() {
 // Connection is ready
 }
 @Disconnect
 public void onDisconnect() {
 if (event.isClosedByClient()) {
 // Client closed
 }
 }
 @Message(encoders = {JacksonEncoder.class}, decoders = {JacksonDecoder.class})
 public Message onMessage(Message message) {
 return message;
 }
}

4. Build and Deploy

mvn clean package

Container-Specific Notes

Tomcat 11+

GlassFish 8+ / Payara 7+

WildFly 35+

Jetty 12+

Servlet Init Parameters

Using atmosphere.xml (Alternative)

Client-Side

<script src="atmosphere.js"></script>
<script>
const subscription = await atmosphere.atmosphere.subscribe(
 {
 url: '/my-chat/chat',
 transport: 'websocket',
 fallbackTransport: 'long-polling',
 trackMessageLength: true,
 contentType: 'application/json'
 },
 {
 open: (response) => console.log('Connected:', response.transport),
 message: (response) => console.log('Message:', response.responseBody),
 close: () => console.log('Disconnected')
 }
);
// Send a message
subscription.push(JSON.stringify({ author: 'Alice', message: 'Hello!' }));
</script>