什么是WebScoket?
WebSocket协议是基于TCP的一种新的网络协议。它实现了浏览器与服务器全双工(full-duplex)通信——允许服务器主动发送信息给客户端。
为什么使用WebScoket?
因为 :HTTP 协议有一个缺陷:通信只能由客户端发起,HTTP 协议做不到服务器主动向客户端推送信息。而WebScoket可以由服务器主动发送信息给客户端。
应用实例:
maven依赖:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
启用WebSocket的支持:创建WebSocketConfig类
package com.iecas.monitor.webscoket.config;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
/**
* @Auther: sy
* @Date: 2020/10/29 20:57
* @Description: 配置websocket后台客户端
*/
@Component
public class WebSocketConfig {
/**
* ServerEndpointExporter 作用
*
* 这个Bean会自动注册使用@ServerEndpoint注解声明的websocket endpoint
*
* @return
*/
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
WebSocketServer:
这就是重点了,核心都在这里。
- 因为WebSocket是类似客户端服务端的形式(采用ws协议),那么这里的WebSocketServer其实就相当于一个ws协议的Controller
- 直接
@ServerEndpoint("/webScoket/send")
、@Component
启用即可,然后在里面实现@OnOpen
开启连接,@onClose
关闭连接,@onMessage
接收消息等方法。 - 新建一个LinkedList webSocketServiceList用于储存多个连接,当需要推送时同时推送多个页面。
- sendInfoOne(String message )方法直接调用发送到前端,scheduledSend()定时监听设置推送条件,符合条件进行推送。
package com.iecas.monitor.webscoket.service;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.LinkedList;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
@Slf4j
@Component
@EnableScheduling // 2.开启定时任务
@ServerEndpoint("/websocket/send")
public class WebSocketGroupService {
/**
* 静态变量,用来记录当前在线连接数。应该把它设计成线程安全的。
*/
private static int onlineCount = 0;
/**
* concurrent包的线程安全Set,用来存放每个客户端对应的MyWebSocket对象。
*/
private static LinkedList<WebSocketGroupService> webSocketServiceList = new LinkedList<>();
/**
* concurrent包的线程安全Set,用来存放要发送的数据
*/
private static LinkedList<String> messageList = new LinkedList<>();
/**
* 与某个客户端的连接会话,需要通过它来给客户端发送数据
*/
private Session session;
/**
* 连接建立成功调用的方法
*/
@OnOpen
public void onOpen(Session session) {
this.session = session;
webSocketServiceList.add(this);
addOnlineCount();
log.info("当前连接数为:" + getOnlineCount());
try {
sendMessage("连接成功");
} catch (IOException e) {
log.error("连接失败!!!!!!");
}
}
/**
* 连接关闭调用的方法
*/
@OnClose
public void onClose() {
webSocketServiceList.remove(this);
subOnlineCount();
log.info("当前在线人数为:" + getOnlineCount());
}
/**
* 收到客户端消息后调用的方法
*
* @param message 客户端发送过来的消息
*/
@OnMessage
public void onMessage(String message, Session session) {
log.info("报文:" + message);
//消息保存到数据库、redis
if (StringUtils.isNotBlank(message)) {
try {
//解析发送的报文
JSONObject jsonObject = JSON.parseObject(message);
for (WebSocketGroupService webSocketGroupService : webSocketServiceList) {
webSocketGroupService.sendMessage(jsonObject.toJSONString());
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* @param session
* @param error
*/
@OnError
public void onError(Session session, Throwable error) {
log.error("错误原因:" + error.getMessage());
error.printStackTrace();
}
/**
* 实现服务器主动推送
*/
public void sendMessage(String message) throws IOException {
this.session.getBasicRemote().sendText(message);
}
@ApiOperation("添加定时任务")
@Scheduled(cron = "0/10 * * * * ?")
private void scheduledSend() {
try {
//发送消息数
for (String message : messageList) {
//发送连接数
for (WebSocketGroupService webSocketGroupService : webSocketServiceList) {
//发送消息
webSocketGroupService.sendMessage(message);
}
}
if (!CollectionUtils.isEmpty(messageList)) {
log.info("发送成功:共发送给[{}]个页面,[{}]个消息", webSocketServiceList.size(), messageList.size());
messageList.clear();
}
} catch (Exception e) {
log.error("发送失败:" + e);
e.printStackTrace();
}
}
/**
* 将发送消息加入缓存
*/
public static void sendInfo(String message) throws IOException {
try {
messageList.add(message);
} catch (Exception e) {
log.error("发送失败:" + e);
e.printStackTrace();
}
}
/**
* 直接发送自定义消息
*/
public static void sendInfoOne(String message ) throws IOException {
try {
for (WebSocketGroupService webSocketGroupService : webSocketServiceList) {
webSocketGroupService.sendMessage(message);
}
log.info("共发送[{}]个消息,成功" + webSocketServiceList.size());
} catch (Exception e) {
log.error("发送失败:" + e);
e.printStackTrace();
}
}
public static synchronized int getOnlineCount() {
return onlineCount;
}
public static synchronized void addOnlineCount() {
WebSocketGroupService.onlineCount++;
}
public static synchronized void subOnlineCount() {
WebSocketGroupService.onlineCount--;
}
}
测试消息推送:
自己的Controller写个方法调用WebSocketServer.sendInfo();即可
package com.iecas.monitor.webscoket.controller;
import com.iecas.monitor.webscoket.service.WebSocketGroupService;
import com.iecas.monitor.webscoket.service.WebSocketService;
import org.java_websocket.server.WebSocketServer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.ModelAndView;
import java.io.IOException;
/**
* WebSocketController
*/
@RestController
public class WebSocketController {
//通过controller返回html界面
@RequestMapping("/index")
public String indexJumpPage() {
return "index";
}
@GetMapping("page")
public ModelAndView page() {
return new ModelAndView("websocket");
}
@GetMapping("/push/{name}")
public ResponseEntity<String> pushToWeb(@PathVariable String name) throws IOException {
WebSocketService.sendInfoByType("测试推送");
return ResponseEntity.ok("MSG SEND SUCCESS");
}
@GetMapping("/send/{name}")
public ResponseEntity<String> send(@PathVariable String name) throws IOException {
WebSocketGroupService.sendInfo("测试推送");
return ResponseEntity.ok("MSG SEND SUCCESS");
}
}
前端HTML5代码:
前端测试代码index.html位置:/src/main/resources/templates下
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>websocket通讯</title>
</head>
<script type = "text/javascript">
var socket;
function openSocket() {
if(typeof(WebSocket) == "undefined") {
console.log("您的浏览器不支持WebSocket");
}else{
console.log("您的浏览器支持WebSocket");
socket = new WebSocket("ws://localhost:8080/websocket/send");
//打开事件
socket.onopen = function() {
console.log("websocket已打开");
//socket.send("这是来自客户端的消息" + location.href + new Date());
};
//获得消息事件
socket.onmessage = function(msg) {
console.log(msg.data);
};
//关闭事件
socket.onclose = function() {
console.log("websocket已关闭");
};
//发生了错误事件
socket.onerror = function() {
console.log("websocket发生了错误");
}
}
}
function sendMessage() {
if(typeof(WebSocket) == "undefined") {
console.log("您的浏览器不支持WebSocket");
}else {
console.log("您的浏览器支持WebSocket");
}
}
</script>
<body>
<p>【message】:
<div><input id="message" name="message" type="text" value="message is null"></div>
<p>【操作】:
<div><a onclick="openSocket()">开启socket</a></div>
<p>【操作】:
<div><a onclick="sendMessage()">发送消息</a></div>
</body>
</html>
在SpringBoot配置文件中加入:
spring:
thymeleaf:
prefix: classpath:/templates/
suffix: .html
mode: LEGACYHTML5
cache: false
运行效果:
显示页面路径:http://localhost:8080/index
调用发送测试路径:http://localhost:8080/send/sy
改动后面参数查看发送效果