The Ultimate Guide to Jetty 9 WebSocket Example

WebSocket is a protocol for providing full-duplex communication channels over a single TCP connection. It is designed to be implemented in web browsers and web servers, but it can be used by any client or server application. Jetty 9 is a Java-based web server and servlet container that supports WebSocket. In this article, we will provide a comprehensive guide to Jetty 9 WebSocket example and explain how to implement it in your Java application.

What is Jetty 9?

Jetty is a Java-based web server and servlet container that provides a lightweight and scalable server for deploying web applications. It can be used as a standalone server or embedded in other applications. Jetty 9 is the latest version of Jetty, which provides improved performance, stability, and security features.

What is WebSocket?

WebSocket is a protocol for providing full-duplex communication channels over a single TCP connection. It is designed to be implemented in web browsers and web servers, but it can be used by any client or server application. WebSocket provides a bi-directional communication channel between the server and the client, allowing real-time data exchange.

What is Jetty 9 WebSocket Example?

Jetty 9 provides support for WebSocket protocol and allows you to create WebSocket endpoints in your Java application. Jetty 9 WebSocket Example is an implementation of WebSocket protocol in a Java web application using Jetty 9 server. It provides an example of how to create a WebSocket endpoint and how to handle WebSocket events.

How to Implement Jetty 9 WebSocket Example?

1. Create a Maven project

To implement Jetty 9 WebSocket Example, you need to create a Maven project in your preferred IDE. You can use Eclipse, IntelliJ IDEA, or NetBeans. Open your IDE and create a new Maven project. Choose a suitable project name and packaging type.

2. Add Jetty and WebSocket dependencies to your project

You need to add Jetty and WebSocket dependencies to your Maven project. Open the pom.xml file and add the following dependencies:

<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-server</artifactId>
<version>9.4.30.v20200611</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-websocket-server</artifactId>
<version>9.4.30.v20200611</version>
</dependency>

3. Create a WebSocket endpoint

You need to create a Java class that implements the javax.websocket.Endpoint interface. This class represents the WebSocket endpoint that handles incoming WebSocket connections. Here is an example of a WebSocket endpoint:

public class MyWebSocketEndpoint extends Endpoint {
    @Override
    public void onOpen(Session session, EndpointConfig config) {
        System.out.println(“WebSocket opened: ” + session.getId());
    }
}


In the above example, we have created a WebSocket endpoint that logs a message when a WebSocket connection is opened. The onOpen() method is called when a WebSocket connection is established.

4. Create a WebSocket server

You need to create a WebSocket server that listens for incoming WebSocket connections. Here is an example of a WebSocket server:

public class MyWebSocketServer {
    public static void main(String[] args) {
        Server server = new Server();
        WebSocketHandler handler = new WebSocketHandler() {
            @Override
            public void configure(WebSocketServletFactory factory) {
                factory.register(MyWebSocketEndpoint.class);
            }
        };
        ServerConnector connector = new ServerConnector(server);
        connector.setPort(8080);
        server.setConnectors(new Connector[] { connector });
        server.setHandler(handler);
        try {
            server.start();
            server.join();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}


In the above example, we have created a WebSocket server that listens on port 8080 for incoming WebSocket connections. The WebSocketHandler class is used to configure the WebSocket servlet factory and register our WebSocket endpoint. The server is started using the start() method and the thread is blocked using the join() method.

5. Test the WebSocket server

Now, you can test your WebSocket server by opening a WebSocket connection in a web browser. You can use the following JavaScript code to open a WebSocket connection:

var ws = new WebSocket(“ws://localhost:8080”);
ws.onopen = function() {
    console.log(“WebSocket opened”);
};
ws.onmessage = function(event) {
    console.log(“WebSocket message received: ” + event.data);
};
ws.onclose = function() {
    console.log(“WebSocket closed”);
};


The above code opens a WebSocket connection to the server and logs messages when the connection is opened, a message is received, or the connection is closed.

Conclusion

Jetty 9 WebSocket Example is a powerful tool for implementing real-time communication in your Java web application. It provides a scalable and lightweight server for handling WebSocket connections and events. In this article, we have provided a comprehensive guide to implementing Jetty 9 WebSocket Example in your Java application. By following the steps outlined in this article, you can create a WebSocket server that provides full-duplex communication channels with your clients.

FAQ

What is the difference between HTTP and WebSocket?

HTTP is a request/response protocol that is used for fetching resources from a server. WebSocket is a bi-directional communication protocol that allows real-time data exchange between the server and the client. HTTP is based on a stateless model, where each request/response is independent of the previous one. WebSocket provides a persistent connection between the server and the client, allowing real-time communication without the overhead of HTTP request/response model.

What are the advantages of using Jetty 9 for WebSocket implementation?

Jetty 9 provides a lightweight and scalable server for WebSocket implementation. It provides support for WebSocket protocol and allows you to create WebSocket endpoints in your Java application. Jetty 9 also provides improved performance, stability, and security features.

Can WebSocket be used with other programming languages?

Yes, WebSocket can be used with other programming languages, not just Java. WebSocket is a protocol that can be implemented in any language that supports TCP/IP sockets. There are WebSocket libraries available for many programming languages, such as Node.js, Python, and Ruby.