用DWR comet+Spring实现服务器推送的例子--网页聊天室

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dwr spring

最近网上看的代码敲下来试试行得通于是拿到这里和大家分享下。

首先下载DWR的JAR包下载地址http://directwebremoting.org/dwr/downloads/index.html

接下来在web工程中加入相应的jar包，因为用到了spring的消息驱动机制如下

接下来是文件结构

---------------------------------------

现在开始写代码了

Message.java 单位信息的承载类

package entity;
import java.util.Date;
/**
 * 作为信息传递的基础类
 * @author WANGHENG
 *
 */
public class Message {
	private int id;
	private String msg;
	private Date time;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getMsg() {
		return msg;
	}
	public void setMsg(String msg) {
		this.msg = msg;
	}
	public Date getTime() {
		return time;
	}
	public void setTime(Date time) {
		this.time = time;
	}
}

ChatMessageEvent.java

package chat;
import org.springframework.context.ApplicationEvent;
/**
 * 自定义事件类
 * @author WANGHENG
 *
 */
public class ChatMessageEvent extends ApplicationEvent{

	public ChatMessageEvent(Object source) {
		super(source);
	}
	private static final long serialVersionUID = -6626763488290315190L;
}

ChatMessageClient.java

package chat;
import java.util.Collection;
import java.util.Date;
import javax.servlet.ServletContext;
import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.ServerContext;
import org.directwebremoting.ServerContextFactory;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.web.context.ServletContextAware;

import entity.Message;
/**
 * MessageEvent事件的监听类
 * 需要spring的支持 利用spring的消息驱动机制
 * @author WANGHENG
 *
 */
@SuppressWarnings("unchecked")
public class ChatMessageClient implements ApplicationListener,
		ServletContextAware {
	private ServletContext ctx;

	@SuppressWarnings("deprecation")
	public void onApplicationEvent(ApplicationEvent event) {
		// 如果事件类型是ChatMessageEvent就执行下面操作
		if (event instanceof ChatMessageEvent) {
			Message msg = (Message) event.getSource();
			ServerContext context = ServerContextFactory.get();
			// 获得客户端所有chat页面script session连接数
			Collection<ScriptSession> sessions = context
					.getScriptSessionsByPage(ctx.getContextPath() + "/chat.jsp");
			for (ScriptSession session : sessions) {
				ScriptBuffer sb = new ScriptBuffer();
				Date time = msg.getTime();
				String s = time.getYear() + "-" + (time.getMonth() + 1) + "-"
						+ time.getDate() + " " + time.getHours() + ":"
						+ time.getMinutes() + ":" + time.getSeconds();
				System.out.println(s);/////////////////s
				// 执行setMessage方法
				sb.appendScript("showMessage({msg: '").appendScript(
						msg.getMsg()).appendScript("', time: '")
						.appendScript(s).appendScript("'})");
				System.out.println(sb.toString());/////////////////sb
				//执行客户端script session方法，相当于浏览器执行JavaScript代码                   
				//上面就会执行客户端浏览器中的showMessage方法，并且传递一个对象过去  
				session.addScript(sb);
			}
		}
	}
	public void setServletContext(ServletContext arg0) {
		this.ctx = arg0;
	}
}

applicationContext-beans.xml

<?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:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
	http://www.springframework.org/schema/aop       
	http://www.springframework.org/schema/aop/spring-aop-3.0.xsd      
	http://www.springframework.org/schema/tx       
	http://www.springframework.org/schema/tx/spring-tx-3.0.xsd      
	http://www.springframework.org/schema/util       
	http://www.springframework.org/schema/util/spring-util-3.0.xsd      
	http://www.springframework.org/schema/context       
	http://www.springframework.org/schema/context/spring-context-3.0.xsd">
	<bean id="chatService" class="chat.ChatService"/> 
	<bean id="chatMessageClient" class="chat.ChatMessageClient"/>
</beans>

dwr.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" 
	"http://getahead.org/dwr/dwr30.dtd">
<dwr>
	<allow>
		<convert match="entity.Message" converter="bean">
			<param name="include" value="msg,time" />
		</convert>
		<create creator="spring" javascript="ChatService">
			<param name="beanName" value="chatService" />
		</create>
	</allow>
</dwr>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
	<!-- 加载Spring容器配置 -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	<!-- 设置Spring容器加载配置文件路径 -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath*:applicationContext-*.xml</param-value>
	</context-param>
	<listener>
		<listener-class>org.directwebremoting.servlet.DwrListener</listener-class>
	</listener>
	<servlet>
		<servlet-name>dwr-invoker</servlet-name>
		<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
		<init-param>
			<param-name>debug</param-name>
			<param-value>true</param-value>
		</init-param>
		<!-- dwr的comet控制 -->
		<init-param>
			<param-name>pollAndCometEnabled</param-name>
			<param-value>true</param-value>
		</init-param>
	</servlet>
	<servlet-mapping>
		<servlet-name>dwr-invoker</servlet-name>
		<url-pattern>/dwr/*</url-pattern>
	</servlet-mapping>
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
</web-app>

ChatService.js文件为空白文件

chat.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<base href="<%=basePath%>">

		<title>My JSP 'chat.jsp' starting page</title>

		<meta http-equiv="pragma" content="no-cache">
		<meta http-equiv="cache-control" content="no-cache">
		<meta http-equiv="expires" content="0">
		<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
		<meta http-equiv="description" content="This is my page">
		<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
		<script type="text/javascript"
			src="${pageContext.request.contextPath }/dwr/engine.js"></script>
		<script type="text/javascript"
			src="${pageContext.request.contextPath }/dwr/util.js"></script>
		<script type="text/javascript"
			src="${pageContext.request.contextPath }/dwr/interface/ChatService.js"></script>
		<script type="text/javascript">         
			function send() {              
				var time = new Date();              
				var content = dwr.util.getValue("content");              
				var name = dwr.util.getValue("userName");              
				var info = encodeURI(encodeURI(name + " say:\n" + content));              
				var msg = {"msg": info, "time": time};              
				dwr.util.setValue("content", "");              
				if (!!content) {                  
					ChatService.sendMessage(msg);              
				} else {                  
					alert("发送的内容不能为空！");              
				}          
			}             
			function showMessage(data) {              
				var message = decodeURI(decodeURI(data.msg));              
				var text = dwr.util.getValue("info");              
				if (!!text) {                    
					dwr.util.setValue("info", text + "\n" + data.time + "  " + message);              
				} else {                  
					dwr.util.setValue("info", data.time + "  " + message);              
				}          
			}      
		</script>
	</head>

	<body onload="dwr.engine.setActiveReverseAjax(true);">
		<textarea rows="20" cols="60" id="info" readonly="readonly"></textarea>
		<hr />
		昵称：<input type="text" id="userName" />
		<br />
		消息：<textarea rows="5" cols="30" id="content"></textarea>
		<input type="button" value=" Send " onclick="send()" style="height: 85px; width: 85px;" />
	</body>
</html>

实现效果