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
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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;
}
}
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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;
}
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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;
}
}
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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>
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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>
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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>
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ChatService.js文件为空白文件
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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>
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实现效果
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这段代码是从http://developer.51cto.com/art/201106/267962.htm ?照搬下来的。
其中engine.js 和 util.js 在附件中