refer to :
https://www.cnblogs.com/web-learn/p/15148141.html
SpringBoot uses WebSocket_springboot websocket_Looking at the Milky Way Blog-CSDN Blog
java
WebSocketConfig
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
/**
* @author: xxt
* @date: 2022/5/23 16:22
* @Description: Enable WebSocket support
*/
@Configuration
public class WebSocketConfig implements ServletContextInitializer {
/**
* The registration of this bean is used to scan the annotation with @ServerEndpoint to become websocket. If you use an external tomcat, you don't need this configuration file
*/
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
}
}
WebSocketServer
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;
/**
* @author: xxt
* @date: 2022/5/23 16:27
* @Description: WebSocket operation class
*/
@ServerEndpoint("/websocket/{userId}")
@Component
@Slf4j
public class WebSocketServer {
// A connection session with a client, which needs to be used to send data to the client
private Session session;
// session collection, store the corresponding session
private static ConcurrentHashMap<Integer, Session> sessionPool = new ConcurrentHashMap<>();
// The thread-safe Set of the concurrent package is used to store the WebSocket object corresponding to each client.
private static CopyOnWriteArraySet<WebSocketSever> webSocketSet = new CopyOnWriteArraySet<>();
/**
* Establish a WebSocket connection
*
* @param session
* @param userId user ID
*/
@OnOpen
public void onOpen(Session session, @PathParam(value = "userId") Integer userId) {
log.info("WebSocket is establishing a connection, connecting user ID: {}", userId);
try {
Session historySession = sessionPool. get(userId);
// historySession is not empty, indicating that someone has logged into the account, and the logged-in WebSocket object should be deleted
if (historySession != null) {
webSocketSet. remove(historySession);
historySession. close();
}
} catch (IOException e) {
log.error("Duplicate login exception, error message:" + e.getMessage(), e);
}
// establish connection
this.session = session;
webSocketSet. add(this);
sessionPool. put(userId, session);
log.info("The connection is established, the current online number is: {}", webSocketSet.size());
}
/**
* An error occurred
*
* @param throwable e
*/
@OnError
public void onError(Throwable throwable) {
throwable. printStackTrace();
}
/**
* Connection closed
*/
@OnClose
public void onClose() {
webSocketSet. remove(this);
log.info("The connection is disconnected, the current online number is: {}", webSocketSet.size());
}
/**
* Receive client messages
*
* @param message received message
*/
@OnMessage
public void onMessage(String message) {
log.info("Received a message from the client: {}", message);
}
/**
* Push messages to specified users
*
* @param userId user ID
* @param message the sent message
*/
public static void sendMessageByUser(Integer userId, String message) {
log.info("User ID: " + userId + ", push content: " + message);
Session session = sessionPool. get(userId);
try {
session.getBasicRemote().sendText(message);
} catch (IOException e) {
log.error("There was an error in pushing the message to the specified user:" + e.getMessage(), e);
}
}
/**
* Group message
*
* @param message the sent message
*/
public static void sendAllMessage(String message) {
log.info("Send message: {}", message);
for (WebSocketSever webSocket : webSocketSet) {
try {
webSocket.session.getBasicRemote().sendText(message);
} catch (IOException e) {
log.error("An error occurred in mass sending message:" + e.getMessage(), e);
}
}
}
}
html5
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>hangge.com</title>
<style>
</style>
<script type="text/javascript">
// used to fill in the input box for sending messages
var messageBox;
// div container for displaying messages
var messageLog;
//WebSocket object
var socket;
//page loaded
window.onload = function() {
messageBox = document.getElementById('messageBox');
messageLog = document.getElementById('messageLog');
}
//Create a socket object and bind all events
function connect() {
//Create socket object
socket = new WebSocket("ws://localhost:8080/websocket/1");
//Listen to all Web socket events
socket.onopen = connectionOpen;
socket.onmessage = messageReceived;
socket.onerror = errorOccurred;
socket.onclose = connectionClosed;
}
// Disconnect button click
function disconnect(){
socket. close();
}
//Send message button click
function sendMessage(){
// get the data to send
var message = messageBox. value;
//Send message through socket
socket. send(message);
// tell the user what just happened
messageLog.innerHTML + = "<br>Send: " + message;
}
//Connection established event response
function connectionOpen(e) {
messageLog.innerHTML + = "<br>--- Socket connection successful ---";
}
//Message received event response
function messageReceived(e){
messageLog.innerHTML + = "<br>Received: " + e.data;
}
// error event response
function errorOccurred(e){
messageLog.innerHTML + = "<br>An error occurred: " + e.data;
}
//connection close event response
function connectionClosed(e) {
messageLog.innerHTML + = "<br>--- Socket connection closed ---";
}
</script>
</head>
<body>
<input id="messageBox" type="text" style="width: 400px;" /><br /><br />
<button onclick="connect()">Connect</button>
<button onclick="sendMessage()">send</button>
<button onclick="disconnect()">Disconnect</button>
<div id="messageLog"></div>
</body>
</html>