websocket使用

2024-02-03 19:23:34

1、导入依赖

<!--websocket依赖-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
    <version>2.6.2</version>
</dependency>

2、编写websocket的配置类

package com.study.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * 开启websocket支持
 */

@Configuration
public class WebSocketConfig {

    //新建websocket配置类
    @Bean
    public ServerEndpointExporter serverEndpointExporter(){
        return new ServerEndpointExporter();
    }

}

3、自定义websocket

package com.study.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArrayList;

@Slf4j
@ServerEndpoint(value = "/websocket")
@Component
public class MyWebSocket {

    //静态变量，用来记录当前在线连接人数，应该把他设计线程安全的
    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 CopyOnWriteArrayList<MyWebSocket> webSockets = new CopyOnWriteArrayList<MyWebSocket>();

    //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;

    /*
    建立连接成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session){
        this.session = session;
        webSockets.add(this); //加入set中
        addOnLineCount(); //在线数+1
        System.out.println("有新连接加入！当前在线人数为：" + getOnLineCount());

        try {
            sendMessage("连接成功");
        }catch (IOException e){
            System.out.println("webSocket IO异常");
        }
    }

    /*
    连接关闭调用的方法
     */
    @OnClose
    public void onClose(){
        webSockets.remove(this); //从set中删除
        subOnLineCount(); //在线数-1
        System.out.println("有一个连接关闭！当前在线人数为：" + getOnLineCount());
    }

    /*
    收到客户端发送的消息后调用的方法

    @param message 客户端发送过来的消息
     */
    @OnMessage
    public void onMessage(String message, Session session){
        System.out.println("来自客户端的消息：" + message);

        //群发消息
        for (MyWebSocket item : webSockets){
            try {
                item.sendMessage(message);
            }catch (IOException e){
                e.printStackTrace();
            }
        }
    }

    /*
    发生错误时调用
     */
    @OnError
    public void one rror(Session session, Throwable error){
        System.out.println("发生错误");
        error.printStackTrace();
    }

    /*
    实现服务器主动推送
    @param message
    @throws IOException
     */
    public void sendMessage(String message) throws IOException{
        this.session.getBasicRemote().sendText(message);
    }

    /*
    群发自定义消息
     */
    public static void sendInfo(String message) throws IOException{
        for (MyWebSocket item : webSockets){
            try {
                item.sendMessage(message);
            }catch (IOException e){
                continue;
            }
        }
    }

    /*
    获取当前连接人数
     */
    public static synchronized int getOnLineCount(){
        return onLineCount;
    }

    /*
    连接数+1
     */
    public static synchronized void addOnLineCount(){
        MyWebSocket.onLineCount++;
    }

    /*
    连接数-1
     */
    public static synchronized void subOnLineCount(){
        MyWebSocket.onLineCount--;
    }
}

4、前端页面编写------前端往后端推送消息

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>My WebSocket</title>
</head>
<body>
    <h1>welcome</h1>
    <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;

    //判断当前的浏览器是否支持WebSocket
    if ('WebSocket' in window){
        webSocket = new WebSocket("ws://localhost:8080/websocket")
    }else {
        alert("Not Support WebSocket")
    }

    //连接错误时的回调方法
    webSocket.onerror = function () {
        setMessageInnerHTML("error")
    }

    //连接成功的回调方法
    webSocket.onopen = function () {
        setMessageInnerHTML("open")
    }

    //接收到消息的回调方法
    webSocket.onmessage = function () {
        setMessageInnerHTML(event.data)
    }

    //连接关闭的回调方法
    webSocket.onclose = function () {
        setMessageInnerHTML("close")
    }

    //监听窗口关闭时间，当窗口关闭时，主动去关闭websocket连接，防止丽娜姐还没断开就关闭窗口，server端会抛异常
    window.onbeforeunload = function () {
        webSocket.close()
    }

    //将消息显示到网页上
    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>

5、前端往后端发送消息测试

6、后端往前端推送消息测试

请求上面那个路径，查看前端

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