java-websocket的搭建非常之容易,没用框架的童鞋可以在这里下载撸主亲自调教好的java-websocket程序:
Apach Tomcat 8.0.3+MyEclipse+maven+JDK1.7
spring4.0以后加入了对websocket技术的支持,撸主目前的项目用的是SSM(springMVC+spring+MyBatis)框架,所
以肯定要首选spring自带的websocket了,好,现在问题来了,撸主在网上各种狂搜猛找,拼凑了几个自称是spring
websocket的东东,下来一看,废物,其中包括从github上down下来的。举个例子,在搭建过程中有个问题,撸主上
谷歌搜索,总共搜出来三页结果共30条左右,前15条是纯英文的 后15条是韩语和日语,而这30条结果都不能解决撸
主的问题,无奈,只好上官网看全英帮助,在撸主惊人的毅力和不懈奋斗下,纠结了两天的spring+websocket整合今
天算是彻底搭建成功,摸索透彻了。
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。
下面言归正传,讲一讲撸主在SSM(springMVC+spring+MyBatis)框架中集成websocket技术的曲折蛋疼直至成功喜悦之路。
- 1 在maven的pom.xml中加入websocket所依赖的jar包,什么,你不知道maven,快去度之或者查看撸主关于maven的博文恶补一下,spring-websocket所依赖的jar包有以下几个:
<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>2.3.0</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-websocket</artifactId> <version>4.0.1.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-messaging</artifactId> <version>4.0.1.RELEASE</version> </dependency>
- 2 更新web.xml中namespace.xsd的版本,
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:websocket="http://www.springframework.org/schema/websocket" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/websocket http://www.springframework.org/schema/websocket/spring-websocket.xsd">
- 3 更新spring框架的jar包至4.0以上(spring-core, spring-context, spring-web and spring-webmvc)
<dependency> <span style="white-space:pre"> </span><groupId>org.springframework</groupId> <artifactId>spring-core</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>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency>
- 4 4.1创建websocket处理类
package com.up.websocket.handler; import org.springframework.web.socket.TextMessage; import org.springframework.web.socket.WebSocketSession; import org.springframework.web.socket.handler.TextWebSocketHandler; public class WebsocketEndPoint extends TextWebSocketHandler { @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception { super.handleTextMessage(session, message); TextMessage returnMessage = new TextMessage(message.getPayload()+" received at server"); session.sendMessage(returnMessage); } }
- 4.2创建握手(handshake)接口
package com.up.websocket; import java.util.Map; import org.springframework.http.server.ServerHttpRequest; import org.springframework.http.server.ServerHttpResponse; import org.springframework.web.socket.WebSocketHandler; import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor; public class HandshakeInterceptor extends HttpSessionHandshakeInterceptor{ @Override public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception { System.out.println("Before Handshake"); return super.beforeHandshake(request, response, wsHandler, attributes); } @Override public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception ex) { System.out.println("After Handshake"); super.afterHandshake(request, response, wsHandler, ex); } }
- 5 处理类和握手协议的spring配置(applicationContext.xml文件)
<bean id="websocket" class="com.up.websocket.handler.WebsocketEndPoint"/> <websocket:handlers> <websocket:mapping path="/websocket" handler="websocket"/> <websocket:handshake-interceptors> <bean class="com.up.websocket.HandshakeInterceptor"/> </websocket:handshake-interceptors> </websocket:handlers>
- 6 客户端页面
<!DOCTYPE html> <html> <head> <title>WebSocket/SockJS Echo Sample (Adapted from Tomcat's echo sample)</title> <style type="text/css"> #connect-container { float: left; width: 400px } #connect-container div { padding: 5px; } #console-container { float: left; margin-left: 15px; width: 400px; } #console { border: 1px solid #CCCCCC; border-right-color: #999999; border-bottom-color: #999999; height: 170px; overflow-y: scroll; padding: 5px; width: 100%; } #console p { padding: 0; margin: 0; } </style> <script src="http://cdn.sockjs.org/sockjs-0.3.min.js"></script> <script type="text/javascript"> var ws = null; var url = null; var transports = []; function setConnected(connected) { document.getElementById('connect').disabled = connected; document.getElementById('disconnect').disabled = !connected; document.getElementById('echo').disabled = !connected; } function connect() { alert("url:"+url); if (!url) { alert('Select whether to use W3C WebSocket or SockJS'); return; } ws = (url.indexOf('sockjs') != -1) ? new SockJS(url, undefined, {protocols_whitelist: transports}) : new WebSocket(url); ws.onopen = function () { setConnected(true); log('Info: connection opened.'); }; ws.onmessage = function (event) { log('Received: ' + event.data); }; ws.onclose = function (event) { setConnected(false); log('Info: connection closed.'); log(event); }; } function disconnect() { if (ws != null) { ws.close(); ws = null; } setConnected(false); } function echo() { if (ws != null) { var message = document.getElementById('message').value; log('Sent: ' + message); ws.send(message); } else { alert('connection not established, please connect.'); } } function updateUrl(urlPath) { if (urlPath.indexOf('sockjs') != -1) { url = urlPath; document.getElementById('sockJsTransportSelect').style.visibility = 'visible'; } else { if (window.location.protocol == 'http:') { url = 'ws://' + window.location.host + urlPath; } else { url = 'wss://' + window.location.host + urlPath; } document.getElementById('sockJsTransportSelect').style.visibility = 'hidden'; } } function updateTransport(transport) { alert(transport); transports = (transport == 'all') ? [] : [transport]; } function log(message) { var console = document.getElementById('console'); var p = document.createElement('p'); p.style.wordWrap = 'break-word'; p.appendChild(document.createTextNode(message)); console.appendChild(p); while (console.childNodes.length > 25) { console.removeChild(console.firstChild); } console.scrollTop = console.scrollHeight; } </script> </head> <body> <noscript><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets rely on Javascript being enabled. Please enable Javascript and reload this page!</h2></noscript> <div> <div id="connect-container"> <input id="radio1" type="radio" name="group1" onclick="updateUrl(''/ZHDM/websocket');"> <label for="radio1">W3C WebSocket</label> <br> <input id="radio2" type="radio" name="group1" onclick="updateUrl('/ZHDM/websocket');"> <label for="radio2">SockJS</label> <div id="sockJsTransportSelect" style="visibility:hidden;"> <span>SockJS transport:</span> <select onchange="updateTransport(this.value)"> <option value="all">all</option> <option value="websocket">websocket</option> <option value="xhr-polling">xhr-polling</option> <option value="jsonp-polling">jsonp-polling</option> <option value="xhr-streaming">xhr-streaming</option> <option value="iframe-eventsource">iframe-eventsource</option> <option value="iframe-htmlfile">iframe-htmlfile</option> </select> </div> <div> <button id="connect" onclick="connect();">Connect</button> <button id="disconnect" disabled="disabled" onclick="disconnect();">Disconnect</button> </div> <div> <textarea id="message" style="width: 350px">Here is a message!</textarea> </div> <div> <button id="echo" onclick="echo();" disabled="disabled">Echo message</button> </div> </div> <div id="console-container"> <div id="console"></div> </div> </div> </body> </html>
- 7 按照以上步骤搭建,根据个人开发环境不同,可能会出现各种问题,下面将在整个搭建过程中遇到的问题总结一下,详见博文:
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spring+websocket整合(springMVC+spring+MyBatis即SSM框架和websocket技术的整合)