Spring Boot 使用websocket

1.搭建Spring Boot项目 wsdemo

1.1 pom.xml

<?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.sunlong</groupId>
    <artifactId>spring-boot-websocket-demo</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

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

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.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-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</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>

1.2 建立WebSocket接口 MyWebSocket.java

package com.sunlong.websocket;

import com.sunlong.service.SendService;
import com.sunlong.utils.SpringUtil;
import org.springframework.stereotype.Controller;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;

/**
 * spring-boot-websocket-demo
 *
 * @Author 孙龙
 * @Date 2017/12/4
 */
@ServerEndpoint(value = "/websocket")
@Controller
public class MyWebSocket {

    //静态变量，用来记录当前在线连接数。
    private static int onlineCount = 0;
    //注入Service只能使用这种方式
    private SendService sendService = SpringUtil.getBean(SendService.class);

    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session) {
        addOnlineCount();           //在线数加1
        System.out.println("有新连接加入！ID是" + session.getId() + "    当前在线人数为" + getOnlineCount());
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose(Session session) {

        subOnlineCount();           //在线数减1
        System.out.println("有一连接关闭！ID是：" + session.getId() + "   当前在线人数为" + getOnlineCount());
        try {
            session.close();
        } catch (IOException e) {
            System.out.println("关闭资源时出错！");
            e.printStackTrace();
        }
    }

    /**
     * 收到客户端消息后调用的方法
     */
    @OnMessage
    public void onMessage(String message, Session session) throws IOException {
        System.out.println("来自客户端的消息:" + message + "   ID是：" + session.getId());

        sendService.sendMessage(session, "服务器消息！");

    }

    /**
     * 发生错误时调用
     */
    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发生错误》》发生时间：" + System.currentTimeMillis() + "  ID是：" + session.getId());

        error.printStackTrace();
    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

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

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

}

1.3发送消息的Service

接口 SendService.java

package com.sunlong.service;

import javax.websocket.Session;
import java.io.IOException;
import java.util.List;

/**
 * spring-boot-websocket-demo
 *
 * @Author 孙龙
 * @Date 2017/11/28
 */
public interface SendService {

    /**
     * 给多个用户发送数据
     *
     * @param sessionList
     * @param message
     * @throws IOException
     */
    void sendBatch(List<Session> sessionList, String message) throws IOException;

    /**
     * 发送消息
     *
     * @param session
     * @param message
     * @throws IOException
     */
    void sendMessage(Session session, String message) throws IOException;
}

实现类 SendServiceImpl.java

package com.sunlong.service.impl;

import com.sunlong.service.SendService;
import org.springframework.stereotype.Service;

import javax.websocket.Session;
import java.io.IOException;
import java.util.List;

/**
 * spring-boot-websocket-demo
 *
 * @Author 孙龙
 * @Date 2017/11/28
 */
@Service
public class SendServiceImpl implements SendService {

    @Override
    public void sendBatch(List<Session> sessionList, String message) throws IOException {
        for (Session session : sessionList) {
            sendMessage(session, message);
        }
    }

    @Override
    public void sendMessage(Session session, String message) throws IOException {
        session.getBasicRemote().sendText(message);
    }
}

1.4获取Spring容器Bean的SpringUtil.java

package com.topsec.util;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class SpringUtil implements ApplicationContextAware {
    private static ApplicationContext applicationContext;

    // 获取applicationContext
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    // 通过name获取 Bean.
    public static Object getBean(String name) {
        return getApplicationContext().getBean(name);
    }

    // 通过class获取Bean.
    public static <T> T getBean(Class<T> clazz) {
        return getApplicationContext().getBean(clazz);
    }

    // 通过name,以及Clazz返回指定的Bean
    public static <T> T getBean(String name, Class<T> clazz) {
        return getApplicationContext().getBean(name, clazz);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (SpringUtil.applicationContext == null) {
            SpringUtil.applicationContext = applicationContext;
        }
    }
}

1.5前端访问页面 ws01.html

在resources/templates目录下

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
    <title>My WebSocket</title>
</head>
<body>
Welcome<br/>
<input id="text" type="text"/>
<button onclick="send()">发送</button>
<button onclick="closeWebSocket()">关闭连接</button>
<div id="message">
</div>
</body>

<script type="text/javascript">
    var websocket = null;
    var host = "";
    if (window.location.protocol == 'http:') {
        host = 'ws://localhost:8585/websocket';
    } else {
        host = 'wss://localhost:8585/websocket';
    }
    //判断当前浏览器是否支持WebSocket

    if ('WebSocket' in window) {
        websocket = new WebSocket(host);
    } else if ('MozWebSocket' in window) {
        websocket = new MozWebSocket(host);
    } else {
        alert("该浏览器不支持WebSocket！");
//        return;
    }

    //连接发生错误的回调方法
    websocket.onerror = function () {
        setMessageInnerHTML("连接出错");
    };

    //连接成功建立的回调方法
    websocket.onopen = function (event) {
        console.log("连接成功");
        setMessageInnerHTML("已连接服务器！");
    }

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

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

    //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
    window.onbeforeunload = function () {
        websocket.close();
    }

    //将消息显示在网页上
    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>

1.6 配置页面映射路径 WebMvcConfig.java

package com.sunlong.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * spring-boot-websocket-demo
 * 该类的作用是可以为ws.html提供便捷的地址映射,只需要在地址栏里面输入localhost:8080/ws,就会找到ws.html
 *
 * @Author 孙龙
 * @Date 2017/11/28
 */
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/ws01").setViewName("/ws01");
    }
    

    /**
     * 配置Spring支持的websocket的类，是必须的
     *
     * @return
     */
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

1.7 端口配置 application.yml

server:
  port: 8585

1.8 启动类WsdemoApplication.java

package com.topsec;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class WsdemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(WsdemoApplication.class, args);
    }
}

1.9 启动

启动项目，打开浏览器访问http://localhost:8585/ws01 给websocket发送消息，测试是否成功；

Github代码示例
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