WebSocket是一種在單個TCP連接上進行全雙工通信的協(xié)議退渗。WebSocket通信協(xié)議于2011年被IETF定為標準RFC 6455床嫌，并由RFC7936補充規(guī)范似炎。WebSocket API也被W3C定為標準灌灾。
WebSocket使得客戶端和服務器之間的數(shù)據(jù)交換變得更加簡單，允許服務端主動向客戶端推送數(shù)據(jù)撵枢。在WebSocket API中，瀏覽器和服務器只需要完成一次握手，兩者之間就直接可以創(chuàng)建持久性的連接诲侮，并進行雙向數(shù)據(jù)傳輸镀虐。
- 協(xié)議中，為我們實現(xiàn)即時服務帶來了兩大好處：
- Header
互相溝通的Header是很小的-大概只有 2 Bytes - Server Push
服務器的推送沟绪，服務器不再被動的接收到瀏覽器的請求之后才返回數(shù)據(jù)刮便，而是在有新數(shù)據(jù)時就主動推送給瀏覽器。
WebSockets允許用戶和服務器之間的流連接绽慈，并允許即時信息交換恨旱。在聊天應用程序的示例中，通過套接字匯集消息坝疼，可以實時與一個或多個用戶交換搜贤，具體取決于誰在服務器上“監(jiān)聽”（連接）。
WebSockets不僅限于聊天/消息傳遞應用程序钝凶。它們適用于需要實時更新和即時信息交換的任何應用程序仪芒。一些示例包括但不限于：現(xiàn)場體育更新，股票行情耕陷，多人游戲掂名，聊天應用，社交媒體等等哟沫。
tcp socket套接字
http是單向傳輸協(xié)議：客戶端->服務器饺蔑，客戶端request服務器response回去
websocket雙工通信雙向的
拉pull推push，http中做不了push（輪詢嗜诀，同源限制就是跨域）
1.加pom依賴猾警，新建模塊：spring-boot-websocker
1.1.加依賴：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.6<version>
<optional>true</optional>
</dependency>
<dependency>
<groupId>com.spring4all</groupId>
<artifactId>swagger-spring-boot-starter</artifactId>
<version>1.8.0.RELEASE<version>
</dependency>
WebSocketConfig類
package com.springboot.websocker.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
/**
WebSocket的配置類
-
開啟了WebSocket支持
*/
@Configuration
public class WebSocketConfig {@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
WebSocketServer類
package com.springboot.websocker.config;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;
//客戶端向服務器端建立WebSocket連接的url
@ServerEndpoint("/websocket")
@Component
public class WebSocketServer {
//靜態(tài)變量，用來記錄當前在線連接數(shù),可選
private static int onlineCount = 0;
//concurrent包的線程安全Set隆敢，用來存放每個客戶端對應的MyWebSocket對象发皿，必須
private static CopyOnWriteArraySet<WebSocketServer> webSocketSet
= new CopyOnWriteArraySet<WebSocketServer>();
//與某個客戶端的連接會話，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");
}
}
/**
* 連接關閉調用的方法
*/
@OnClose
public void onClose() {
webSocketSet.remove(this); //從set中刪除
subOnlineCount(); //在線數(shù)減1
System.out.println("有連接關閉筑公！當前在線人數(shù)為" + getOnlineCount());
}
/**
* 收到客戶端消息后調用的方法
*
* @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--;
}
}
WebSocketController類
package com.springboot.websocker.controller;
import com.springboot.websocker.config.WebSocketServer;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.io.IOException;
@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";
}
}
底層統(tǒng)統(tǒng)不要捕獲異常雳窟，所有的異常在controller捕獲異常
create和onload只執(zhí)行一次
前端代碼：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<link rel="stylesheet" type="text/css" href="css/font-awesome.min.css" />
<meta name="viewport" content="width=device-width,initial-scale=1,shrink-to-fit=no">
<meta name="viewport" content="width=device-width,initial-scale=1,maximun-scale=1">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>websocket示例</title>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<style type="text/css">
/* 手機 /
@media only screen and (min-width : 320px) {
.col-xs-12{
flex: 0 0 100%;
}
}
/ 平板 /
@media only screen and (min-width : 768px) {
.col-md-6{
flex: 0 0 50%;
}
}
/ 中等屏幕 /
@media only screen and (min-width : 992px) {
.col-lg-4{
flex: 0 0 33.33%;
}
}
/ 寬屏設備 */
@media only screen and (min-width : 1200px) {
.col-xl-3{
flex: 0 0 25%;
}
}
body{
background: url(img/20190414131210.png);
}
.header{
right: 5px;
left: 1px;
position: fixed;
top: 0;
width: 100%;
height: 40px;
background-color:rgb(70,154,254);
display:flex;
justify-content: space-between;
}
.header img{
padding: 10upx;
width: 25px;
height: 25px;
}
.foot{
margin-top: 400px;
}
.foots{
height: 40px;
width: 100%;
right: 5px;
left: 3px;
position: absolute;
background-color:rgb(70,154,254);
}
.foots img{
width: 30px;
height: 30px;
padding: 12px;
}
</style>
</head>
<body>
<div id="app">
<div class="header">
<div><img src="img/xiaoyuhao.png"/></div>
<div>
<img src="img/phone.png"/>
<img src="img/people.png"/>
</div>
</div>
<div id="box">
<div id="pic">
<h3>消息顯示</h3>
<ul>
<li v-for="(message, index) in messages" :key="index">
{{message}}
</li>
</ul>
</div>
</div>
<div class="foot">
<!-- <h3>發(fā)送消息 </h3> -->
<input type="text" v-model="sendMsg" />
<button type="button" @click="send">發(fā)送</button>
</div>
<div class="foots">
<img src="img/voi.png"/>
<img src="img/ablum.png"/>
<img src="img/money.png"/>
<img src="img/shipin.png"/>
<img src="img/xiaolian.png"/>
</div>
</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，指定要連接的服務器地址和端口匣屡，建立連接
socket = new WebSocket("ws://192.168.43.83:8080/websocket");
//打開連接
socket.onopen = function() {
console.log("Socket已打開");
};
//獲得服務端推送的消息
socket.onmessage = function(msg) {
console.log(msg.data);
_this.messages.push(msg.data);
console.log(_this.messages);
};
//關閉連接
socket.onclose = function() {
console.log("Socket已關閉");
};
//發(fā)送錯誤
socket.onerror = function() {
alert("Socket發(fā)生了錯誤");
}
},
watch: {
// 如果 `messages` 發(fā)生改變封救，這個函數(shù)就會運行
messages: function(newMsg, oldMsg) {
this.messages = newMsg;
},
},
methods: {
send: function() {
socket.send(this.sendMsg);
}
}
})
</script>
</body>
</html>
