pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
websocket配置（沒有此配置會導致連接websocket失敗）
package com.websocket.websocket.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
package com.websocket.websocket.Controller;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicInteger;
@ServerEndpoint("/ws/asset")
@Component
public class WebSocketController {
private static final AtomicInteger OnlineCount = new AtomicInteger(0);
// concurrent包的線程安全Set，用來存放每個客戶端對應的Session對象。
private static CopyOnWriteArraySet<Session> SessionSet = new CopyOnWriteArraySet<Session>();
/**
* 連接建立成功調用的方法
*/
@OnOpen
public void onOpen(Session session) {
SessionSet.add(session);
int cnt = OnlineCount.incrementAndGet(); // 在線數加1
System.out.println("有連接加入，當前連接數爲：" + cnt);
SendMessage(session, "連接成功");
}
/**
* 連接關閉調用的方法
*/
@OnClose
public void onClose(Session session) {
SessionSet.remove(session);
int cnt = OnlineCount.decrementAndGet();
System.out.println("有連接關閉，當前連接數爲：" + cnt);
}
/**
* 收到客戶端消息後調用的方法
*
* @param message
* 客戶端發送過來的消息
*/
@OnMessage
public void onMessage(String message, Session session) {
System.out.println("來自客戶端的消息：" + message);
SendMessage(session, "收到消息，消息內容："+message);
}
/**
* 出現錯誤
* @param session
* @param error
*/
@OnError
public void onError(Session session, Throwable error) {
System.out.println("發生錯誤：" + error.getMessage() + "，Session ID：" + session.getId());
error.printStackTrace();
}
/**
* 發送消息，實踐表明，每次瀏覽器刷新，session會發生變化。
* @param session
* @param message
*/
public static void SendMessage(Session session, String message) {
try {
session.getBasicRemote().sendText(String.format("%s (From Server，Session ID=%s)",message,session.getId()));
} catch (IOException e) {
System.out.println("發送消息出錯：" + e.getMessage());
e.printStackTrace();
}
}
/**
* 羣發消息
* @param message
* @throws IOException
*/
public static void BroadCastInfo(String message) throws IOException {
for (Session session : SessionSet) {
if(session.isOpen()){
SendMessage(session, message);
}
}
}
/**
* 指定Session發送消息
* @param sessionId
* @param message
* @throws IOException
*/
public static void SendMessage(String sessionId,String message) throws IOException {
Session session = null;
for (Session s : SessionSet) {
if(s.getId().equals(sessionId)){
session = s;
break;
}
}
if(session!=null){
SendMessage(session, message);
} else {
System.out.println("沒有找到你指定ID的會話：" + sessionId);
}
}
}
html（客戶端）
<!DOCTYPE HTML>
<html>
<head>
<meta charset="UTF-8">
<title>My WebSocket</title>
</head>
<body>
Welcome<br/>
<input id="text" type="text" /><button onclick="send()">Send</button> <button onclick="closeWebSocket()">Close</button>
<div id="message">
</div>
</body>
<script type="text/javascript">
var websocket = null;
//判斷當前瀏覽器是否支持WebSocket
if('WebSocket' in window){
websocket = new WebSocket("ws://localhost:8080/ws/asset");
}
else{
alert('Not support websocket')
}
//連接發生錯誤的回調方法
websocket.onerror = function(){
setMessageInnerHTML("error");
};
//連接成功建立的回調方法
websocket.onopen = function(event){
setMessageInnerHTML("open");
}
//接收到消息的回調方法
websocket.onmessage = function(event){
setMessageInnerHTML(event.data);
}
//連接關閉的回調方法
websocket.onclose = function(){
setMessageInnerHTML("close");
}
//監聽窗口關閉事件，當窗口關閉時，主動去關閉websocket連接，防止連接還沒斷開就關閉窗口，server端會拋異常。
window.onbeforeunload = function(){
websocket.close();
}
//將消息顯示在網頁上
function setMessageInnerHTML(innerHTML){
document.getElementById('message').innerHTML += innerHTML + '<br/>';
}
//關閉連接
function closeWebSocket(){
websocket.close();
}
//發送消息
function send(){
var message = document.getElementById('text').value;
websocket.send(message);
}
</script>
</html>