这篇文章主要介绍了详解 spring boot 实现 websocket, 小编觉得挺不错的, 现在分享给大家, 也给大家做个参考一起跟随小编过来看看吧
前言
QQ 这类即时通讯工具多数是以桌面应用的方式存在在没有 websocket 出现之前, 如果开发一个网页版的即时通讯应用, 则需要定时刷新页面或定时调用 ajax 请求, 这无疑会加大服务器的负载和增加了客户端的流量而 websocket 的出现, 则完美的解决了这些问题
spring boot 对 websocket 进行了封装, 这对实现一个 websocket 网页即时通讯应用来说, 变得非常简单
一准备工作
pom.xml 引入
- <dependency>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-websocket</artifactId>
- </dependency>
完整的 pom.xml 文件代码如下:
- <?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-16</artifactId>
- <version>0.0.1-SNAPSHOT</version>
- <packaging>jar</packaging>
- <name>spring-boot-16</name>
- <description>Demo project for Spring Boot</description>
- <parent>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-parent</artifactId>
- <version>1.5.3.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-web</artifactId>
- </dependency>
- <dependency>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-websocket</artifactId>
- </dependency>
- <dependency>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-devtools</artifactId>
- <scope>runtime</scope>
- </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>
二代码编写
1. 创建名为 WebSocketConfig.java 的类来配置 websocket, 并继承抽象类 AbstractWebSocketMessageBrokerConfigurer
此类声明 @EnableWebSocketMessageBroker 的注解
- package com.example;
- import org.springframework.context.annotation.Configuration;
- import org.springframework.messaging.simp.config.MessageBrokerRegistry;
- import org.springframework.web.socket.config.annotation.AbstractWebSocketMessageBrokerConfigurer;
- import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
- import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
- @Configuration
- @EnableWebSocketMessageBroker
- public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
- @Override
- public void configureMessageBroker(MessageBrokerRegistry config) {
- config.enableSimpleBroker("/topic");
- config.setApplicationDestinationPrefixes("/app");
- }
- @Override
- public void registerStompEndpoints(StompEndpointRegistry registry) {
- registry.addEndpoint("/my-websocket").withSockJS();
- }
- }
这里配置了以 / app 开头的 websocket 请求 url 和名为 my-websocket 的 endpoint(端点)
2. 编写一个 DTO 类来承载消息:
- package com.example;
- public class SocketMessage {
- public String message;
- public String date;
- }
3. 创建 App.java 类, 用于启用 spring boot 和用于接收发送消息的控制器
- package com.example;
- import java.text.DateFormat;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.boot.SpringApplication;
- import org.springframework.boot.autoconfigure.SpringBootApplication;
- import org.springframework.messaging.handler.annotation.MessageMapping;
- import org.springframework.messaging.handler.annotation.SendTo;
- import org.springframework.messaging.simp.SimpMessagingTemplate;
- import org.springframework.scheduling.annotation.EnableScheduling;
- import org.springframework.scheduling.annotation.Scheduled;
- import org.springframework.stereotype.Controller;
- import org.springframework.web.bind.annotation.GetMapping;
- @Controller
- @EnableScheduling
- @SpringBootApplication
- public class App {
- public static void main(String[] args) {
- SpringApplication.run(App.class, args);
- }
- @Autowired
- private SimpMessagingTemplate messagingTemplate;
- @GetMapping("/")
- public String index() {
- return "index";
- }
- @MessageMapping("/send")
- @SendTo("/topic/send")
- public SocketMessage send(SocketMessage message) throws Exception {
- DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- message.date = df.format(new Date());
- return message;
- }
- @Scheduled(fixedRate = 1000)
- @SendTo("/topic/callback")
- public Object callback() throws Exception {
- // 发现消息
- DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- messagingTemplate.convertAndSend("/topic/callback", df.format(new Date()));
- return "callback";
- }
- }
send 方法用于接收客户端发送过来的 websocket 请求
@EnableScheduling 注解为: 启用 spring boot 的定时任务, 这与 callback 方法相呼应, 用于每隔 1 秒推送服务器端的时间
4. 在 resources/templates 目录下创建 index.html 文件:
- <!DOCTYPE html>
- <html>
- <head>
- <title > 玩转 spring bootwebsocket</title>
- <script src="//cdn.bootCSS.com/angular.js/1.5.6/angular.min.js"></script>
- <script src="https://cdn.bootcss.com/sockjs-client/1.1.4/sockjs.min.js"></script>
- <script src="https://cdn.bootcss.com/stomp.js/2.3.3/stomp.min.js"></script>
- <script type="text/javascript">
- /*<![CDATA[*/
- var stompClient = null;
- var app = angular.module('app', []);
- app.controller('MainController', function($rootScope, $scope, $http) {
- $scope.data = {
- // 连接状态
- connected : false,
- // 消息
- message : '',
- rows : []
- };
- // 连接
- $scope.connect = function() {
- var socket = new SockJS('/my-websocket');
- stompClient = Stomp.over(socket);
- stompClient.connect({}, function(frame) {
- // 注册发送消息
- stompClient.subscribe('/topic/send', function(msg) {
- $scope.data.rows.push(JSON.parse(msg.body));
- $scope.data.connected = true;
- $scope.$apply();
- });
- // 注册推送时间回调
- stompClient.subscribe('/topic/callback', function(r) {
- $scope.data.time = '当前服务器时间:' + r.body;
- $scope.data.connected = true;
- $scope.$apply();
- });
- $scope.data.connected = true;
- $scope.$apply();
- });
- };
- $scope.disconnect = function() {
- if (stompClient != null) {
- stompClient.disconnect();
- }
- $scope.data.connected = false;
- }
- $scope.send = function() {
- stompClient.send("/app/send", {}, JSON.stringify({
- 'message' : $scope.data.message
- }));
- }
- });
- /*]]>*/
- </script>
- </head>
- <body ng-app="app" ng-controller="MainController">
- <h2 > 玩转 spring bootwebsocket</h2>
- <h4>
出处: 刘冬博客 <a href="http://www.cnblogs.com/goodhelper" rel="external nofollow">http://www.cnblogs.com/goodhelper</a>
- </h4>
- <label>WebSocket 连接状态:</label>
- <button type="button" ng-disabled="data.connected" ng-click="connect()"> 连接 </button>
- <button type="button" ng-click="disconnect()"
- ng-disabled="!data.connected"> 断开 </button>
- <br />
- <br />
- <div ng-show="data.connected">
- <label>{{data.time}}</label> <br /> <br /> <input type="text"
- ng-model="data.message" placeholder="请输入内容..." />
- <button ng-click="send()" type="button"> 发送 </button>
<br /> <br /> 消息列表: <br />
- <table>
- <thead>
- <tr>
- <th > 内容 </th>
- <th > 时间 </th>
- </tr>
- </thead>
- <tbody>
- <tr ng-repeat="row in data.rows">
- <td>{{row.message}}</td>
- <td>{{row.date}}</td>
- </tr>
- </tbody>
- </table>
- </div>
- </body>
- </html>
除了引用 angular.js 的 CDN 文件外, 还需要引用 sockjs 和 stomp
完整的项目结构, 如下图所示:
三运行效果
点击连接按钮, 出现发送消息的输入框并接收到服务器端的时间推送
输入发送内容并点击发送按钮后, 页面显示出刚才发送的消息
点击断开按钮, 则服务器端不会再推送消息
总结
在开发一个基于 web 的即时通讯应用的过程中, 我们还需考虑 session 的机制
还需要一个集合来承载当前的在线用户, 并做一个定时任务, 其目的是用轮询的方式定时处理在线用户的状态, 有哪些用户在线, 又有哪些用户离线
参考:
- http://spring.io/guides/gs/scheduling-tasks/
- http://spring.io/guides/gs/messaging-stomp-websocket/
代码地址: https://github.com/carter659/spring-boot-16
来源: http://www.phperz.com/article/18/0317/356723.html