使用spring-websocket包搭建websocket服务

怼烎@ 2022-06-10 01:59 215阅读 0赞

websocket是Html5新增加特性之一，目的是浏览器与服务端建立全双工的通信方式，解决http请求-响应带来过多的资源消耗，同时对特殊场景应用提供了全新的实现方式，比如聊天、股票交易、游戏等对对实时性要求较高的行业领域。

Spring4开始支持WebSocket，也支持通过STOMP协议连接JMS消息服务器如ActiveMQ等。WebSocket是目前唯一真正实现全双工通信的服务器向客户端推的互联网技术，与长连接和轮询技术相比，WebSocket的优越性不言自明，长连接的连接资源（线程资源）随着连接数量的增多必会耗尽，客户端轮询会给服务器造成很大的压力，而WebSocket是在物理层非网络层建立一条客户端至服务器的长连接，以此来保证服务器向客户端的即时推送，既不耗费线程资源，又不会不断向服务器轮询请求。

1.spring 4.0及以上增加了WebSocket的支持(这里使用4.3.8.RELEASE)   
2.spring 支持STOMP协议的WebSocket通信   
3.应对不支持 WebSocket 的场景，许多浏览器不支持 WebSocket 协议；SockJS 是 WebSocket 技术的一种模拟。SockJS 会 尽可能对应 WebSocket API，但如果 WebSocket 技术 不可用的话，会从如下 方案中挑选最优可行方案：

XHR streaming
    XDR streaming
    iFrame event source
    iFrame HTML file
    XHR polling
    XDR polling
    iFrame XHR polling
    JSONP polling

4.WebSocket 是发送和接收消息的 底层API，而SockJS 是在 WebSocket 之上的 API；最后 STOMP（面向消息的简单文本协议）是基于 SockJS 的高级API   
5.SockJS 所处理的URL 是 “http: ” 或 “https: ” 模式   
6.WebSocket 所处理的URL 是“ws: ” or “wss: ” 模式

下面我们来建立一个websocket实例

一。 建立maven工程

dom.xml 加入websocket所依赖的包

<dependency>  
        <groupId>javax.servlet</groupId>  
        <artifactId>javax.servlet-api</artifactId>  
        <version>3.1.0</version>  
    </dependency>  
    <dependency>  
        <groupId>com.fasterxml.jackson.core</groupId>  
        <artifactId>jackson-core</artifactId>  
        <version>2.8.0</version>  
    </dependency>  
    <dependency>  
        <groupId>com.fasterxml.jackson.core</groupId>  
        <artifactId>jackson-databind</artifactId>  
        <version>2.8.0</version>  
    </dependency> 
    <dependency>  
       <groupId>org.springframework</groupId>  
       <artifactId>spring-websocket</artifactId>  
       <version>4.3.7.RELEASE</version>  
    </dependency>  
    <dependency>  
       <groupId>org.springframework</groupId>  
       <artifactId>spring-messaging</artifactId>  
       <version>4.3.7.RELEASE</version>  
    </dependency>

spring框架加入 spring-core, spring-context, spring-web ,spring-webmvc 类库，贴出完整的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>org.jstudioframework</groupId>
        <artifactId>jstudio-webstocket1</artifactId>
        <version>1.0-SNAPSHOT</version>
        <packaging>war</packaging>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            
            <spring.version>4.3.7.RELEASE</spring.version>
            <slf4j.version>1.6.6</slf4j.version>
            <jackson.version>2.8.4</jackson.version>
            <servlet-api.version>3.1.0</servlet-api.version>
        </properties>
    
    
        <dependencies>
            
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-log4j12</artifactId>
                <version>${slf4j.version}</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-core</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-beans</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-web</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-webmvc</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-aop</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context-support</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-test</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-websocket</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-messaging</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>${servlet-api.version}</version>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-core</artifactId>
                <version>${jackson.version}</version>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>${jackson.version}</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                
                <plugin>
                    <groupId>org.apache.tomcat.maven</groupId>
                    <artifactId>tomcat7-maven-plugin</artifactId>
                    <configuration>
                        <port>8080</port>
                        <path>/ws</path>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    
    </project>

二。创建一个Websocket处理器

可以扩展 AbstractWebSocketHandler ,也可以扩展 TextWebSocketHandler(文本处理器)，TextWebSocketHandler 继承 AbstractWebSocketHandler

package org.jstudioframework.websoket.handler;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.web.socket.CloseStatus;
    import org.springframework.web.socket.TextMessage;
    import org.springframework.web.socket.WebSocketSession;
    import org.springframework.web.socket.handler.TextWebSocketHandler;
    
    import java.io.IOException;
    import java.util.ArrayList;
    
    /**
     * Websocket处理器
     */
    
    public class WebSocketHandler extends TextWebSocketHandler {
        private final static Logger LOGGER = LoggerFactory.getLogger(WebSocketHandler.class);
    
        //已建立连接的用户
        private static final ArrayList<WebSocketSession> users = new ArrayList<WebSocketSession>();
    
        /**
         * 处理前端发送的文本信息
         * js调用websocket.send时候，会调用该方法
         *
         * @param session
         * @param message
         * @throws Exception
         */
        @Override
        protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
            String username = (String) session.getAttributes().get("WEBSOCKET_USERNAME");
            // 获取提交过来的消息详情
            LOGGER.debug("收到用户 " + username + "的消息:" + message.toString());
            //回复一条信息，
            session.sendMessage(new TextMessage("reply msg:" + message.getPayload()));
        }
    
    
        /**
         * 当新连接建立的时候，被调用
         * 连接成功时候，会触发页面上onOpen方法
         *
         * @param session
         * @throws Exception
         */
        @Override
        public void afterConnectionEstablished(WebSocketSession session) throws Exception {
            users.add(session);
            String username = (String) session.getAttributes().get("WEBSOCKET_USERNAME");
            LOGGER.info("用户 " + username + " Connection Established");
            session.sendMessage(new TextMessage(username + " connect"));
            session.sendMessage(new TextMessage("hello wellcome"));
        }
    
        /**
         * 当连接关闭时被调用
         *
         * @param session
         * @param status
         * @throws Exception
         */
        @Override
        public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
            String username = (String) session.getAttributes().get("WEBSOCKET_USERNAME");
            LOGGER.info("用户 " + username + " Connection closed. Status: " + status);
            users.remove(session);
        }
    
        /**
         * 传输错误时调用
         *
         * @param session
         * @param exception
         * @throws Exception
         */
        @Override
        public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
            String username = (String) session.getAttributes().get("WEBSOCKET_USERNAME");
            if (session.isOpen()) {
                session.close();
            }
            LOGGER.debug("用户: " + username + " websocket connection closed......");
            users.remove(session);
        }
    
        /**
         * 给所有在线用户发送消息
         *
         * @param message
         */
        public void sendMessageToUsers(TextMessage message) {
            for (WebSocketSession user : users) {
                try {
                    if (user.isOpen()) {
                        user.sendMessage(message);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    
        /**
         * 给某个用户发送消息
         *
         * @param userName
         * @param message
         */
        public void sendMessageToUser(String userName, TextMessage message) {
            for (WebSocketSession user : users) {
                if (user.getAttributes().get("WEBSOCKET_USERNAME").equals(userName)) {
                    try {
                        if (user.isOpen()) {
                            user.sendMessage(message);
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    break;
                }
            }
        }
    }

三。创建一个WebSocket握手拦截器

package org.jstudioframework.websoket.interceptor;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.http.server.ServerHttpRequest;
    import org.springframework.http.server.ServerHttpResponse;
    import org.springframework.http.server.ServletServerHttpRequest;
    import org.springframework.web.socket.WebSocketHandler;
    import org.springframework.web.socket.server.HandshakeInterceptor;
    
    import javax.servlet.http.HttpSession;
    import java.util.Map;
    
    /**
     * WebSocket握手拦截器
     */
    public class WebSocketHandshakeInterceptor implements HandshakeInterceptor {
        private final static Logger LOGGER = LoggerFactory.getLogger(WebSocketHandshakeInterceptor.class);
    
        public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Map<String, Object> attributes) throws Exception {
            if (request instanceof ServletServerHttpRequest) {
                ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
                HttpSession session = servletRequest.getServletRequest().getSession(false);
                if (session != null) {
                    //使用userName区分WebSocketHandler，以便定向发送消息
                    String userName = (String) session.getAttribute("SESSION_USERNAME");
                    if (userName == null) {
                        userName = "system-" + session.getId();
                    }
                    attributes.put("WEBSOCKET_USERNAME", userName);
                }
            }
            return true;
        }
    
        public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Exception e) {
            System.out.println("After Handshake");
        }
    }

四。 Spring WebSocket的配置文件，采用的是注解的方式

package org.jstudioframework.websoket.config;
    
    import org.jstudioframework.websoket.handler.WebSocketHandler;
    import org.jstudioframework.websoket.interceptor.WebSocketHandshakeInterceptor;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    import org.springframework.web.socket.config.annotation.*;
    import org.springframework.web.socket.handler.TextWebSocketHandler;
    
    /**
     * Spring WebSocket的配置，这里采用的是注解的方式
     */
    
    @Configuration
    //@EnableWebMvc//这个标注可以不加，如果有加，要extends WebMvcConfigurerAdapter
    @EnableWebSocket
    public class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
    
        public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
            //1.注册WebSocket
            String websocket_url = "/websocket/socketServer.do";                        //设置websocket的地址
            registry.addHandler(webSocketHandler(), websocket_url).                          //注册Handler
                    addInterceptors(new WebSocketHandshakeInterceptor());                   //注册Interceptor
    
            //2.注册SockJS，提供SockJS支持(主要是兼容ie8)
            String sockjs_url = "/sockjs/socketServer.do";                              //设置sockjs的地址
            registry.addHandler(webSocketHandler(), sockjs_url).                            //注册Handler
                    addInterceptors(new WebSocketHandshakeInterceptor()).                   //注册Interceptor
                    withSockJS();                                                           //支持sockjs协议
        }
    
        @Bean
        public TextWebSocketHandler webSocketHandler() {
            return new WebSocketHandler();
        }
    }

五。创建Controller测试类

package org.jstudioframework.websoket.controller;
    
    import org.jstudioframework.websoket.handler.WebSocketHandler;
    import org.springframework.context.annotation.Bean;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.socket.TextMessage;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    /**
     * 测试类
     */
    
    @Controller
    public class PageController {
    
        @Bean//这个注解会从Spring容器拿出Bean
        public WebSocketHandler infoHandler() {
            return new WebSocketHandler();
        }
    
        @RequestMapping("/login")
        public void login(HttpServletRequest request, HttpServletResponse response) throws Exception {
            String username = request.getParameter("username");
            System.out.println(username + "登录");
            HttpSession session = request.getSession();
            session.setAttribute("SESSION_USERNAME", username);
            response.sendRedirect("websocket.jsp");
        }
    
        @RequestMapping("/send")
        @ResponseBody
        public String send(HttpServletRequest request) {
            String username = request.getParameter("username");
            infoHandler().sendMessageToUser(username, new TextMessage("你好，欢迎测试！！！！"));
            return null;
        }
    }

六。测试页面

1.登录页面，输入用户名称  login.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
             pageEncoding="utf-8" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <body>
    <h2>Wellcome</h2>
    
    <body>
    <form action="login">
        登录名：<input type="text" name="username"/>
        <input type="submit" value="登录"/>
    </form>
    </body>
    </body>
    </html>

2.消息发送接收页面 websocket.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
             pageEncoding="utf-8" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>Java API for WebSocket (JSR-356)</title>
    </head>
    <body>
    <script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
    <script type="text/javascript" src="http://cdn.bootcss.com/sockjs-client/1.1.1/sockjs.js"></script>
    <script type="text/javascript">
        var websocket = null;
        if ('WebSocket' in window) {
            //Websocket的连接
            websocket = new WebSocket("ws://localhost:8080/ws/websocket/socketServer.do");//WebSocket对应的地址
        }
        else if ('MozWebSocket' in window) {
            //Websocket的连接
            websocket = new MozWebSocket("ws://localhost:8080/ws/websocket/socketServer.do");//SockJS对应的地址
        }
        else {
            //SockJS的连接
            websocket = new SockJS("http://localhost:8080/ws/sockjs/socketServer.do");    //SockJS对应的地址
        }
        websocket.onopen = onOpen;
        websocket.onmessage = onMessage;
        websocket.onerror = onError;
        websocket.onclose = onClose;
    
        function onOpen(openEvt) {
            //alert(openEvt.Data);
        }
    
        function onMessage(evt) {
            alert(evt.data);
        }
        function onError() {
        }
        function onClose() {
        }
    
        function doSend() {
            if (websocket.readyState == websocket.OPEN) {
                var msg = document.getElementById("inputMsg").value;
                websocket.send(msg);//调用后台handleTextMessage方法
                alert("发送成功!");
            } else {
                alert("连接失败!");
            }
        }
    
        window.close = function () {
            websocket.onclose();
        }
    </script>
    请输入：<textarea rows="3" cols="100" id="inputMsg" name="inputMsg"></textarea>
    <button οnclick="doSend();">发送</button>
    </body>
    </html>

七。spring的配置

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:mvc="http://www.springframework.org/schema/mvc"
           xsi:schemaLocation="http://www.springframework.org/schema/beans  
                            http://www.springframework.org/schema/beans/spring-beans-3.1.xsd  
                            http://www.springframework.org/schema/context  
                            http://www.springframework.org/schema/context/spring-context-3.1.xsd  
                            http://www.springframework.org/schema/mvc  
                            http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
        
        <context:annotation-config />
        
        <mvc:annotation-driven />
        
        <context:component-scan base-package="org.jstudioframework.websoket" />
    
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/WEB-INF/views/" />
            <property name="suffix" value=".jsp" />
        </bean>
    </beans>

八。web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
             version="3.1">
        <welcome-file-list>
            <welcome-file>index.jsp</welcome-file>
        </welcome-file-list>
    
        <context-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/*.xml</param-value>
        </context-param>
    
        <listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>
    
        <servlet>
            <servlet-name>dispatcherServlet</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:spring/*.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
            <async-supported>true</async-supported>
        </servlet>
        <servlet-mapping>
            <servlet-name>dispatcherServlet</servlet-name>
            <url-pattern>/</url-pattern>
        </servlet-mapping>
    
        <filter>
            <filter-name>encodingFilter</filter-name>
            <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
            <async-supported>true</async-supported>
            <init-param>
                <param-name>encoding</param-name>
                <param-value>UTF-8</param-value>
            </init-param>
            <init-param>
                <param-name>forceEncoding</param-name>
                <param-value>true</param-value>
            </init-param>
        </filter>
    
        <filter-mapping>
            <filter-name>encodingFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    </web-app>

所有的servlet和filter都要加<async-supported>true</async-supported>

九。测试

![Center][]

![Center 1][]

工程代码实例下载地址

[http://download.csdn.net/download/zsg88/9933921  
][http_download.csdn.net_download_zsg88_9933921]

[Center]: /images/20220610/95943ac985ce4bafa7b3119479375d61.png
[Center 1]: /images/20220610/33eb9a9a4b874ef887aa5f0cc5454aec.png
[http_download.csdn.net_download_zsg88_9933921]: http://download.csdn.net/download/zsg88/9933921