WebSocket练习

实现内容

• 客户端页面index.htm可以输入消息点击发送，通过ws协议发送到服务器端
• 服务器端收到客户端消息后，广播给各个客户端
• 服务器端页面server.html，可以输入消息，点击发送，通过ws双工通信推送给客户端
• 客户端有显示服务器端广播消息的区域

目录结构

image.png

添加pom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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>spring-boot-websocket</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-websocket</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <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>

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

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

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

• WebSocketConfig

package com.example.spring_boot_websocket.config;

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

/**
 * WebSocket配置类
 */
@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

• WebSocketServer

package com.example.spring_boot_websocket.config;

import org.springframework.stereotype.Component;

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

/**
 * WebSocket的服务端
 * 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(“/websocket”)@Component启用即可，
 * 然后在里面实现@OnOpen,@onClose,@onMessage等方法
 */
@ServerEndpoint("/websocket")
@Component
public class WebSocketServer {

    //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 CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();

    //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;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1
        System.out.println("有新窗口开始监听,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() {
        webSocketSet.remove(this);  //从set中删除
        subOnlineCount();           //在线数减1
        System.out.println("有连接关闭！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) {
        System.out.println("收到客户端的信息:" + message);
        //群发消息
        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("发生错误");
        error.printStackTrace();
    }

    /**
     * 实现服务器主动推送
     */
    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 {
        System.out.println("推送消息内容:" + 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

package com.example.spring_boot_websocket.controller;

import com.example.spring_boot_websocket.config.WebSocketServer;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.io.IOException;


@Controller
public class WebSocketController {

    @RequestMapping("/socket")
    public String openTencent(){
        return "tencent";
    }

    /**
     * 推送数据
     * @param say
     * @return
     */
    @RequestMapping("/socket/push")
    public String pushMsg(@RequestParam("say") String say) {
        try {
            WebSocketServer.sendInfo("服务器推送消息"+say);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "tencent";
    }
}

静态页面

• index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>WebSocket</title>
</head>
<body>
<h2>WebSocket</h2>
<h2>客户端</h2>
<input type="text" id="say" name="say">
<input type="button" id="sendSay" name="sendSay" value="发送">

<h2>消息记录</h2>
<textarea id="message" cols="60px" rows="40px" ></textarea>

<script>
    var socket;
    var say = document.getElementById("say");
    var sendSay = document.getElementById("sendSay");
    var message= document.getElementById("message");
    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");
        //实现化WebSocket对象，指定要连接的服务器地址与端口建立连接
        socket = new WebSocket("ws://localhost:8080/websocket");
        //打开事件
        socket.onopen = function () {
            console.log("Socket已打开");
            // socket.send("这是来自客户端的消息:" + new Date());
        };
        sendSay.onclick = function sendSay(){
            socket.send("这是来自客户端的消息:" + say.value)
        };
        //获得消息事件
        socket.onmessage = function (msg) {
            console.log(msg.data);
            // alert(msg.data);
            var messageInfo = message.value;
            messageInfo = messageInfo + " \n " + msg.data;
            message.value = messageInfo;
        };
        //关闭事件
        socket.onclose = function () {
            console.log("Socket已关闭");
        };
        //发生了错误事件
        socket.onerror = function () {
            alert("Socket发生了错误");
        }
    }
</script>

</body>
</html>

• tencent.html

<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Server</title>
</head>
<body>
<h2>这里是服务器：</h2>
<form action="/socket/push">
    <input type="text" id="say" name="say">
    <input type="submit" id="sendSay" name="sendSay" value="群发">
</form>

</body>
</html>

实现效果

image.png image.png image.png