Setting Up Spring Websocket with Jetty

Oct 13, 2025 by pinkandtrash.com 85 views

Introduction

In this article, we will explore how to implement plain WebSockets using Spring and Jetty. WebSockets provide a bi-directional communication channel between a client and a server, allowing for real-time data exchange. Spring provides a simple and efficient way to implement WebSockets using its WebSocket API, which is built on top of the Jetty WebSocket implementation.

What are WebSockets?

WebSockets are a protocol that enables bidirectional, real-time communication between a client and a server over the web. They allow for efficient and low-latency communication, making them ideal for applications that require real-time updates, such as live updates, gaming, and chat applications.

Why Use Spring Websocket?

Spring Websocket is a powerful and flexible framework for building WebSocket-based applications. It provides a simple and efficient way to implement WebSockets, with features such as:

Bi-directional communication: Spring Websocket allows for bi-directional communication between a client and a server, enabling real-time data exchange.
Low-latency: Spring Websocket provides low-latency communication, making it ideal for applications that require real-time updates.
Scalability: Spring Websocket is designed to scale horizontally, making it suitable for large-scale applications.
Flexibility: Spring Websocket provides a flexible architecture, allowing developers to customize and extend the framework to meet their specific needs.

Setting Up Spring Websocket with Jetty

To set up Spring Websocket with Jetty, you will need to add the following dependencies to your project:

Spring Websocket: spring-websocket
Jetty: org.eclipse.jetty.websocket:websocket-api and org.eclipse.jetty.websocket:websocket-client

Here is an example of how to add these dependencies to your pom.xml file (if you are using Maven):

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-websocket</artifactId>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty.websocket</groupId>
        <artifactId>websocket-api</artifactId>
        <version>9.4.43.v20210629</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty.websocket</groupId>
        <artifactId>websocket-client</artifactId>
        <version>9.4.43.v20210629</version>
    </dependency>
</dependencies>

Configuring Spring Websocket with Jetty

To configure Spring Websocket with Jetty, you will need to create a WebSocketConfig class that extends AbstractWebSocketMessageBrokerConfigurer. In this class, you can configure the WebSocket endpoint, message broker, and other settings.

Here is an example of how to configure Spring Websocket with Jetty:

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
    registry.addHandler(myHandler(), &quot;/myHandler&quot;).setAllowedOrigins(&quot;*&quot;);
}

@Bean
public WebSocketHandler myHandler() {
    return new MyHandler();
}

}

Implementing the WebSocket Handler

To implement the WebSocket handler, you will need to create a class that implements the WebSocketHandler interface. In this class, you can handle incoming WebSocket messages and send messages back to the client.

Here is an example of how to implement the WebSocket handler:

@Component
public class MyHandler implements WebSocketHandler {
@Override
public void afterConnectionEstablished(WebSocketSession session, WebSocketHandler webSocketHandler) {
    System.out.println(&quot;Connection established&quot;);
}

@Override
public void handleMessage(WebSocketSession session, WebSocketMessage&lt;?&gt; message) {
    System.out.println(&quot;Received message: &quot; + message.getPayload());
    try {
        session.sendMessage(new TextMessage(&quot;Hello, client!&quot;));
    } catch (IOException e) {
        System.out.println(&quot;Error sending message: &quot; + e.getMessage());
    }
}

@Override
public void handleTransportError(WebSocketSession session, Throwable exception) {
    System.out.println(&quot;Transport error: &quot; + exception.getMessage());
}

@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
    System.out.println(&quot;Connection closed&quot;);
}

@Override
public boolean supportsPartialMessages() {
    return false;
}

}

Testing the WebSocket Application

To test the WebSocket application, you will need to use a WebSocket client, such as the Chrome DevTools or a third-party library like ws in Node.js.

Here is an example of how to test the WebSocket application using the Chrome DevTools:

Open the Chrome DevTools by pressing F12 or by right-clicking on the page and selecting Inspect.
Switch to the Console tab.
Type ws://localhost:8080/myHandler and press Enter.
You should see a WebSocket connection established.
Type Hello, server! and press Enter.
You should see a response from the server, Hello, client!.

Conclusion

In this article, we explored how to implement plain WebSockets using Spring and Jetty. We covered the basics of WebSockets, the benefits of using Spring Websocket, and how to set up and configure Spring Websocket with Jetty. We also implemented a simple WebSocket handler and tested the application using the Chrome DevTools.

Troubleshooting Common Issues

Here are some common issues that you may encounter when implementing Spring Websocket with Jetty:

NullPointerException: If you encounter a NullPointerException when trying to establish a WebSocket connection, it may be due to a missing dependency or a configuration issue.
Connection refused: If you encounter a Connection refused error when trying to establish a WebSocket connection, it may be due to a firewall or a network issue.
Invalid WebSocket URL: If you encounter an Invalid WebSocket URL error when trying to establish a WebSocket connection, it may be due to a typo or a configuration issue.

Best Practices

Here are some best practices to keep in mind when implementing Spring Websocket with Jetty:

Use a secure connection: Always use a secure connection (HTTPS) when implementing WebSockets to prevent eavesdropping and tampering.
Use a WebSocket library: Use a WebSocket library, such as ws in Node.js, to simplify the implementation of WebSockets.
Test thoroughly: Test your WebSocket application thoroughly to ensure that it works correctly and securely.
Monitor performance: Monitor the performance of your WebSocket application to ensure that it is scalable and efficient.
Q&A: Implementing Plain WebSockets with Spring/Jetty =====================================================

Q: What are the benefits of using Spring Websocket?

A: Spring Websocket provides a simple and efficient way to implement WebSockets, with features such as bi-directional communication, low-latency, scalability, and flexibility. It also provides a flexible architecture, allowing developers to customize and extend the framework to meet their specific needs.

Q: How do I set up Spring Websocket with Jetty?

A: To set up Spring Websocket with Jetty, you will need to add the following dependencies to your project:

Spring Websocket: spring-websocket
Jetty: org.eclipse.jetty.websocket:websocket-api and org.eclipse.jetty.websocket:websocket-client

You will also need to create a WebSocketConfig class that extends AbstractWebSocketMessageBrokerConfigurer and configure the WebSocket endpoint, message broker, and other settings.

Q: How do I implement the WebSocket handler?

A: To implement the WebSocket handler, you will need to create a class that implements the WebSocketHandler interface. In this class, you can handle incoming WebSocket messages and send messages back to the client.

Here is an example of how to implement the WebSocket handler:

@Component
public class MyHandler implements WebSocketHandler {
@Override
public void afterConnectionEstablished(WebSocketSession session, WebSocketHandler webSocketHandler) {
    System.out.println(&quot;Connection established&quot;);
}

@Override
public void handleMessage(WebSocketSession session, WebSocketMessage&lt;?&gt; message) {
    System.out.println(&quot;Received message: &quot; + message.getPayload());
    try {
        session.sendMessage(new TextMessage(&quot;Hello, client!&quot;));
    } catch (IOException e) {
        System.out.println(&quot;Error sending message: &quot; + e.getMessage());
    }
}

@Override
public void handleTransportError(WebSocketSession session, Throwable exception) {
    System.out.println(&quot;Transport error: &quot; + exception.getMessage());
}

@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
    System.out.println(&quot;Connection closed&quot;);
}

@Override
public boolean supportsPartialMessages() {
    return false;
}

}

Q: How do I test the WebSocket application?

A: To test the WebSocket application, you will need to use a WebSocket client, such as the Chrome DevTools or a third-party library like ws in Node.js.

Here is an example of how to test the WebSocket application using the Chrome DevTools:

Open the Chrome DevTools by pressing F12 or by right-clicking on the page and selecting Inspect.
Switch to the Console tab.
Type ws://localhost:8080/myHandler and press Enter.
You should see a WebSocket connection established.
Type Hello, server! and press Enter.
You should see a response from the server, Hello, client!.

Q: What are some common issues that I may encounter when implementing Spring Websocket with Jetty?

A: Here are some common issues that you may encounter when implementing Spring Websocket with Jetty:

NullPointerException: If you encounter a NullPointerException when trying to establish a WebSocket connection, it may be due to a missing dependency or a configuration issue.
Connection refused: If you encounter a Connection refused error when trying to establish a WebSocket connection, it may be due to a firewall or a network issue.
Invalid WebSocket URL: If you encounter an Invalid WebSocket URL error when trying to establish a WebSocket connection, it may be due to a typo or a configuration issue.

Q: What are some best practices to keep in mind when implementing Spring Websocket with Jetty?

A: Here are some best practices to keep in mind when implementing Spring Websocket with Jetty:

Use a secure connection: Always use a secure connection (HTTPS) when implementing WebSockets to prevent eavesdropping and tampering.
Use a WebSocket library: Use a WebSocket library, such as ws in Node.js, to simplify the implementation of WebSockets.
Test thoroughly: Test your WebSocket application thoroughly to ensure that it works correctly and securely.
Monitor performance: Monitor the performance of your WebSocket application to ensure that it is scalable and efficient.

Q: Can I use Spring Websocket with other WebSocket implementations?

A: Yes, you can use Spring Websocket with other WebSocket implementations, such as Apache Tomcat or Undertow. However, you will need to configure the WebSocket endpoint and message broker accordingly.

Q: How do I handle errors in the WebSocket handler?

A: To handle errors in the WebSocket handler, you can override the handleTransportError method and handle the error accordingly.

Here is an example of how to handle errors in the WebSocket handler:

@Override
public void handleTransportError(WebSocketSession session, Throwable exception) {
    System.out.println("Transport error: " + exception.getMessage());
    // Handle the error accordingly
}

Q: Can I use Spring Websocket with other messaging protocols?

A: Yes, you can use Spring Websocket with other messaging protocols, such as STOMP or MQTT. However, you will need to configure the message broker and endpoint accordingly.

Q: How do I implement authentication and authorization in the WebSocket handler?

A: To implement authentication and authorization in the WebSocket handler, you can use Spring Security to authenticate and authorize the WebSocket connections.

Here is an example of how to implement authentication and authorization in the WebSocket handler:

@Component
public class MyHandler implements WebSocketHandler {
@Override
public void afterConnectionEstablished(WebSocketSession session, WebSocketHandler webSocketHandler) {
    // Authenticate the WebSocket connection
    if (!session.getPrincipal().isAuthenticated()) {
        // Handle the authentication failure
    }
}

@Override
public void handleMessage(WebSocketSession session, WebSocketMessage&lt;?&gt; message) {
    // Authorize the WebSocket message
    if (!session.getPrincipal().hasRole(&quot;ROLE_ADMIN&quot;)) {
        // Handle the authorization failure
    }
}

}

Conclusion

In this article, we have covered some of the most frequently asked questions about implementing plain WebSockets with Spring and Jetty. We have discussed the benefits of using Spring Websocket, how to set up and configure Spring Websocket with Jetty, and how to implement the WebSocket handler. We have also covered some common issues that you may encounter when implementing Spring Websocket with Jetty and some best practices to keep in mind.