这次给大家说一下自己对websocket + spring boot结合使用的一些经验
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首先websocket是一个持久化的协议，实现了浏览器与服务器的全双工通信。不再像http那样，只有在浏览器发出request之后才有response，websocket能实现服务器主动向浏览器发出消息。
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下面我们用spring boot来实现一下：
在spring boot的文档中，介绍了我们需要配置的文件
// pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter (){
return new ServerEndpointExporter();
}
}
@ServerEndpoint("/websocket")
@Component
public class MyWebSocket {
private static int onlineCount = 0;
private static CopyOnWriteArraySet<MyWebSocket> webSocketSet = new CopyOnWriteArraySet<>();
private Session session;
@OnOpen
public void onOpen (Session session){
this.session = session;
webSocketSet.add(this);
addOnlineCount();
System.out.println("有新链接加入!当前在线人数为" + getOnlineCount());
}
@OnClose
public void onClose (){
webSocketSet.remove(this);
subOnlineCount();
System.out.println("有一链接关闭!当前在线人数为" + getOnlineCount());
}
@OnMessage
public void onMessage (String message, Session session) throws IOException {
System.out.println("来自客户端的消息:" + message);
// 群发消息
for ( MyWebSocket item : webSocketSet ){
item.sendMessage(message);
}
}
public void sendMessage (String message) throws IOException {
this.session.getBasicRemote().sendText(message);
}
public static synchronized int getOnlineCount (){
return MyWebSocket.onlineCount;
}
public static synchronized void addOnlineCount (){
MyWebSocket.onlineCount++;
}
public static synchronized void subOnlineCount (){
MyWebSocket.onlineCount--;
}
}
<!DOCTYPE HTML>
<html>
<head>
<base href="localhost://localhost:8080/">
<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;
//判断当前浏览器是否支持WebSocket
if (‘WebSocket‘ in window) {
websocket = new WebSocket("ws://localhost:8080/websocket");
}
else {
alert(‘Not support websocket‘)
}
//连接发生错误的回调方法
websocket.onerror = function () {
setMessageInnerHTML("error");
};
//连接成功建立的回调方法
websocket.onopen = function (event) {
setMessageInnerHTML("open");
}
//接收到消息的回调方法
websocket.onmessage = function (event) {
setMessageInnerHTML(event.data);
}
//连接关闭的回调方法
websocket.onclose = function () {
setMessageInnerHTML("close");
}
//监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function () {
websocket.close();
}
//将消息显示在网页上
function setMessageInnerHTML(innerHTML) {
document.getElementById(‘message‘).innerHTML += innerHTML + ‘<br/>‘;
}
//关闭连接
function closeWebSocket() {
websocket.close();
}
//发送消息
function send() {
var message = document.getElementById(‘text‘).value;
websocket.send(message);
}
</script>
</html>
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原文：http://zk-chs.iteye.com/blog/2285329