WebSocket是一種在單個TCP傳輸控制協(xié)議連接上進行全雙工全雙工通信的協(xié)議迹栓。WebSocket使得客戶端和服務(wù)器之間的數(shù)據(jù)交換變得更加簡單仑乌，允許服務(wù)端主動向客戶端推送數(shù)據(jù)。在WebSocket API中，瀏覽器和服務(wù)器只需要完成一次握手缩焦，兩者之間就直接可以創(chuàng)建持久性的連接读虏，并進行雙向數(shù)據(jù)傳輸。
Websocket的使用
添加依賴
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
Websocket配置類
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
Websocket服務(wù)類
@ServerEndpoint("/websocket")
@Component
public class WebSocketServer {
//靜態(tài)變量袁滥，用來記錄當(dāng)前在線連接數(shù),可選
private static int onlineCount = 0;
//concurrent包的線程安全Set盖桥，用來存放每個客戶端對應(yīng)的MyWebSocket對象，必須
private static CopyOnWriteArraySet<WebSocketServer> webSocketSet
= new CopyOnWriteArraySet<WebSocketServer>();
//與某個客戶端的連接會話题翻，需要通過它來給客戶端發(fā)送數(shù)據(jù),必須
private Session session;
/**
* 連接建立成功調(diào)用的方法
*/
@OnOpen
public void onOpen(Session session) {
this.session = session;
webSocketSet.add(this); //將客戶端加入set中
addOnlineCount(); //在線數(shù)加1
System.out.println("有新窗口開始監(jiān)聽,當(dāng)前在線人數(shù)為"
+ getOnlineCount());
try {
sendMessage("連接成功");
} catch (IOException e) {
System.out.println("WebSocket IO異常");
}
}
/**
* 連接關(guān)閉調(diào)用的方法
*/
@OnClose
public void onClose() {
webSocketSet.remove(this); //從set中刪除
subOnlineCount(); //在線數(shù)減1
System.out.println("有連接關(guān)閉揩徊！當(dāng)前在線人數(shù)為" + getOnlineCount());
}
/**
* 收到客戶端消息后調(diào)用的方法
*
* @param message 客戶端發(fā)送過來的消息
*/
@OnMessage
public void onMessage(String message, Session session) {
System.out.println("收到客戶端的信息:" + message);
//群發(fā)消息
for (WebSocketServer item : webSocketSet) {
try {
item.sendMessage(message);
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* @param session
* @param error
*/
@OnError
public void onError(Session session, Throwable error) {
System.out.println("發(fā)生錯誤");
error.printStackTrace();
}
/**
* 實現(xiàn)服務(wù)器主動推送
*/
public void sendMessage(String message) throws IOException {
this.session.getBasicRemote().sendText(message);
}
/**
* 群發(fā)自定義消息
*/
public static void sendInfo(String message) throws IOException {
System.out.println("推送消息內(nèi)容:" + message);
for (WebSocketServer item : webSocketSet) {
try {
item.sendMessage(message);
} catch (IOException e) {
continue;
}
}
}
public static synchronized int getOnlineCount() {
return onlineCount;
}
public static synchronized void addOnlineCount() {
WebSocketServer.onlineCount++;
}
public static synchronized void subOnlineCount() {
WebSocketServer.onlineCount--;
}
}
Websocket控制層
@RestController
public class WebSocketController {
//推送數(shù)據(jù)接口
@GetMapping("/socket/push")
public String pushMsg(String message) {
try {
WebSocketServer.sendInfo(message);
} catch (IOException e) {
e.printStackTrace();
}
return "success";
}
}
前端調(diào)用
<html>
<head>
<meta charset="utf-8" />
<title>websocket示例</title>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<h3>消息顯示</h3>
<ul>
<li v-for="(message, index) in messages" :key="index">
{{message}}
</li>
</ul>
<h3>發(fā)送消息 </h3>
<input type="text" v-model="sendMsg" />
<button type="button" @click="send">發(fā)送</button>
</div>
<script type="text/javascript">
var socket;
var app = new Vue({
el: '#app',
data: {
messages: [],
sendMsg: ''
},
created: function() {
var _this = this;
//創(chuàng)建WebSocket對象，指定要連接的服務(wù)器地址和端口嵌赠，建立連接
socket = new WebSocket("ws://localhost:8080/websocket");
//打開連接
socket.onopen = function() {
console.log("Socket已打開");
};
//獲得服務(wù)端推送的消息
socket.onmessage = function(msg) {
console.log(msg.data);
_this.messages.push(msg.data);
console.log(_this.messages);
};
//關(guān)閉連接
socket.onclose = function() {
console.log("Socket已關(guān)閉");
};
//發(fā)送錯誤
socket.onerror = function() {
alert("Socket發(fā)生了錯誤");
}
},
watch: {
// 如果
messages 發(fā)生改變塑荒，這個函數(shù)就會運行messages: function(newMsg, oldMsg) {
this.messages = newMsg;
var n = new Notification('Title', {//標(biāo)題
body : newMsg[newMsg.length - 1]
});
//兩秒后關(guān)閉通知
setTimeout(function() {
n.close();
}, 2000);
},
},
methods: {
send: function() {
socket.send(this.sendMsg);
}
}
})
</script>
</body>
</html>
