How to use WebSocket to implement instant chat function in Java-javaTutorial-php.cn

How to use WebSocket to implement instant chat function in Java

王林

Release： 2023-12-18 08:43:58

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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:

JDK 1.8 or higher
Maven build tool
IDE, such as Eclipse Or IntelliJ IDEA

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>

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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();
    }

}

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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);
    }
}

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In the above code, we use a sessions list to manage all connected WebSocket sessions. afterConnectionEstablishedThe 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. afterConnectionClosedThe 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>

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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.

So far, we have completed all the code for using WebSocket to implement the instant chat function in Java. Next, we give a brief explanation of the entire process.

Users access the

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.

After running the project, multiple users can implement the instant chat function by accessing the

chat.html page.

To sum up, this article introduces how to use WebSocket to implement instant chat function in Java and provides specific code examples. Hope this article helps you!

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