SpringBoot之WebSocket服务搭建

WebSockets 彻底改变了 Web，将笨拙、缓慢的实时交互转变为时尚、低延迟的体验，使其成为动态、用户友好型应用程序的首选。

1.创建SpringBoot工程

在Intellij IDEA工具中使用SpringBoot项目初始化向导新建一个工程,如工程名为yuan-websocket-demo

2. pom.xml中引入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.0.RELEASE</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>yuan-websocket-demo</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
       
        <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.68</version>
        </dependency>

    </dependencies>

</project>

3. application.yml配置

server:
  port: 2001
  max-http-header-size: 8192
spring:
  thymeleaf:
    cache: false

4. 主启动类

主启动类中标注开启WebSoket的注解@EnableWebSocket

package org.yuan;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.web.socket.config.annotation.EnableWebSocket;

/**
 * <p>
 * Description: <br>
 * <p>
 * Author:jinshengyuan <br>
 * Datetime: 2020-05-29 15:00
 * </p>
 *
 */
@SpringBootApplication
@EnableWebSocket
@ServletComponentScan
public class MyWebSocketApplication {
    public static void main(String[] args) {
        SpringApplication.run(MyWebSocketApplication.class, args);
    }
}

5. WebSocket配置类

配置类WebSocketConfig .java如下

package org.yuan.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
/**
 * 用于扫描和注册所有携带ServerEndPoint注解的实例。
 * <p>
 * 注意:若部署到外部容器，则无需配置此类。
 */
@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

6. 编写MyWebSocket服务类

package org.yuan.mysoket;

import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;
@Component
@ServerEndpoint("/myChat")
public class MyWebSocket {
    private static int onLineCount = 0;//记录在线连接数，应该做成线程安全的

    //线程安全set,用来存储每个客户的MyWebSocket对象
    private static CopyOnWriteArraySet<MyWebSocket> myWebSockets = new CopyOnWriteArraySet<>();

    //与某个客户端的连接会话，需要通过它来给客户发送数据
    private Session session;

    /**
     * <p>
     * Description: 连接建立成功后调用的方法<br>
     * <p>
     * Author:jinshengyuan <br>
     * Datetime: 2020/5/28 22:25
     * </p>
     *
     * @return
     * @since 2020/5/28 22:25
     */
    @OnOpen
    public void onOpen(Session session) {
        System.out.println("连接了哦");
        this.session = session;
        myWebSockets.add(this);
        addOnlineCount();
        System.out.println();
    }

    /**
     * <p>
     * Description: 关闭会话连接<br>
     * <p>
     * Author:jinshengyuan <br>
     * Datetime: 2020/5/28 22:39
     * </p>
     *
     * @param
     * @param
     * @return
     * @since 2020/5/28 22:39
     */
    @OnClose
    public void onClose(Session session) {
        myWebSockets.remove(this);
        subOnlineCount();
    }


    /**
     * <p>
     * Description: 发送消息<br>
     * <p>
     * Author:jinshengyuan <br>
     * Datetime: 2020/5/28 22:39
     * </p>
     * @since 2020/5/28 22:39
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        System.out.println("来自客户端的消息：" + message);
        for (MyWebSocket socket : myWebSockets) {
            try {
                socket.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
                continue;
            }
        }
    }


    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发送消息失败");
        error.printStackTrace();
    }

    public static synchronized void addOnlineCount() {
        MyWebSocket.onLineCount++;
    }

    public static synchronized void subOnlineCount() {
        MyWebSocket.onLineCount--;
    }

    public static synchronized int getOnLineCount() {
        return onLineCount;
    }
}

7. 编写测试页面

index.html如下

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>WebSocket</title>
</head>
<body>
Welcome to WebSocket demo<br>
请输入消息：<input type="texarea" id="msg">
<button onclick="send()">发送消息</button>
<hr>
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr>

<div id="message"></div>
</body>
</html>
<script>
    let webSocket = null;
    if ('WebSocket' in window) {
        webSocket = new WebSocket('ws://localhost:2001/myChat')
    } else {
        alert("当前浏览器不支持WebSocket协议");
    }
    //连接出错时的回调
    webSocket.onerror = () => {
        setMessageInnerHTML("WebSocket连接失败");
    }
    //连接成功建立的回调
    webSocket.onopen = () => {
        setMessageInnerHTML("WebSocket连接成功");
    }
    //接收到消息的回调方法
    webSocket.onmessage = function (event) {
        setMessageInnerHTML(event.data);
    }

    //监听窗口关闭事件
    window.onbeforeunload = () => {
        closeWebSocket();
    }

    //关闭WebSocket连接
    closeWebSocket = () => {
        webSocket.close();
    }

    const send = () => {
        let message = document.getElementById("msg").value;
        webSocket.send(message);
    }

    function setMessageInnerHTML(innerHTML) {
        document.getElementById("message").innerHTML += innerHTML + '<br>';
    }
</script>

启动SpringBoot应用后,浏览器中输入地址进行测试：http://localhost:2001