How to use WebSocket to implement instant chat function in Java
With the rapid development of the Internet, instant messaging has become an indispensable part of people's lives. As a full-duplex communication protocol, WebSocket has gradually replaced the traditional HTTP protocol and become one of the important technologies for realizing instant messaging functions. This article will introduce how to use WebSocket to implement instant chat function in Java and provide specific code examples.
First, we need to prepare the following environment and tools:
Next, we start to implement the instant chat function.
Step 1: Create a Java-based WebSocket server
We use the Spring Boot framework in Java to create the WebSocket server. Spring Boot provides WebSocket's developer-friendly API and convenient configuration. Before creating the WebSocket server, we need to create a Spring Boot project.
First, create a new Spring Boot project in the IDE and introduce the following dependencies:
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-websocket</artifactId> </dependency> </dependencies>
Then, create a configuration class named WebSocketConfig and add the following code:
@Configuration @EnableWebSocket public class WebSocketConfig implements WebSocketConfigurer { @Override public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) { registry.addHandler(chatWebSocketHandler(), "/chat").setAllowedOrigins("*"); } @Bean public WebSocketHandler chatWebSocketHandler() { return new ChatWebSocketHandler(); } }
In the above code, we enable WebSocket through the @EnableWebSocket
annotation, and register a WebSocket processor named chatWebSocketHandler
through the registerWebSocketHandlers
method. The path of the processor is "/chat", we can customize the path as needed.
Step 2: Implement the WebSocket processor
Next, we need to implement the WebSocket processor to process and manage WebSocket connections. In this processor, we will implement the functionality of receiving and sending messages.
Create a class named ChatWebSocketHandler and implement the WebSocketHandler
interface. In this class, we need to override some methods:
public class ChatWebSocketHandler extends TextWebSocketHandler { private static final List<WebSocketSession> sessions = new CopyOnWriteArrayList<>(); @Override public void afterConnectionEstablished(WebSocketSession session) throws Exception { sessions.add(session); } @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception { for (WebSocketSession webSocketSession : sessions) { webSocketSession.sendMessage(message); } } @Override public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception { sessions.remove(session); } }
In the above code, we use a sessions
list to manage all connected WebSocket sessions. afterConnectionEstablished
The method will be called after the connection is established and we add the session to the list. The handleTextMessage
method is used to receive and process messages. We send the received messages to all connected sessions. afterConnectionClosed
The method will be called after the connection is closed, and we need to remove the session from the list.
Step 3: Front-end page
Finally, we need to create a front-end page to implement the user's instant chat function.
Create an HTML file named chat.html
in the static folder of the project and add the following code:
<!DOCTYPE html> <html> <head> <title>Chat</title> <script src="https://code.jquery.com/jquery-3.5.1.min.js"></script> </head> <body> <div id="messages"></div> <input id="input" type="text" /> <button id="send">Send</button> <script> var socket = new WebSocket("ws://localhost:8080/chat"); socket.onmessage = function(event) { var message = event.data; $("#messages").append("<p>" + message + "</p>"); }; $("#send").click(function() { var message = $("#input").val(); socket.send(message); $("#input").val(""); }); </script> </body> </html>
In the above code, we pass # The ##WebSocket object establishes a connection with the server and uses the
onmessage event to handle the received message. When the user clicks the Send button, we send the text in the input box to the server.
chat.html page through a browser and establish a WebSocket connection with the server. When the user enters a message in the input box and clicks the Send button, the browser will send the message to the server. After the server receives the message, it sends the message to all connected sessions. After the session receives the message, it displays it on the page.
chat.html page.
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