`

[转]一个用DWR做的聊天记录

DWRJavaJSPBeanAjax 
阅读更多
在开发前请先配好你的DWR包和配置文件

dwr.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting
     2.0//EN" "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
  <allow>
    <create creator="new" javascript="JavaChat">
      <param name="class" value="cn.com.thinkbank.service.JavaChat" />
    </create>
   
    <convert converter="bean" match="cn.com.thinkbank.bean.ChatMsg">
    </convert>
  </allow>
</dwr>


web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<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>
</servlet>

<servlet-mapping>
  <servlet-name>dwr-invoker</servlet-name>
  <url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
</web-app>


ChatMsg.java

package cn.com.thinkbank.bean;

public class ChatMsg {
private String text;

/**
  * @return 返回 text。
  */
public String getText() {
  return text;
}

/**
  * @param text
  *            要设置的 text。
  */
public void setText(String text) {
  this.text = text;
}

public ChatMsg() {
  // TODO 自动生成构造函数存根
}

public ChatMsg(String text) {
  // TODO 自动生成构造函数存根
  this.text = text;
}

}


Chat.jsp页面


<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head>
  <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">
  <script. type="text/javascript" src="/Chat/dwr/util.js"></script>
  <script. type="text/javascript" src="/Chat/dwr/engine.js"></script>
  <script. type="text/javascript" src="/Chat/dwr/interface/JavaChat.js"></script>
  <script. type="text/javascript">
<!--
function sendMessage(){
JavaChat.addMessage(dwr.util.getValue("text"));
}
//-->
</script>
  <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
</head>

<body nload="DWREngine.setActiveReverseAjax(true)">
  <h1>
   反向Ajax的聊天室
  </h1>
  <DIV style="width:460px;height: 200px;border:1px solid;#999999">
   <UL id="charLog"></UL>
  </DIV>
  <P>
   输入您的聊天信息
   <INPUT type="text" id="text" nkeypress="dwr.util.onReturn(event,sendMessage)" />
   <INPUT type="button" value="发送" nclick="sendMessage()" />
  </p>
</body>
</html>


JavaChat.java

package cn.com.thinkbank.service;

import java.util.Collection;
import java.util.LinkedList;

import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.proxy.dwr.Util;


import cn.com.thinkbank.bean.ChatMsg;

public class JavaChat {
private LinkedList<ChatMsg> messages = new LinkedList<ChatMsg>();
public void addMessage(String text){
  if(text !=null && text.trim().length()>0){
   messages.addFirst(new ChatMsg(text));
   System.out.println(messages.size());
   while(messages.size()>10){
    messages.removeLast();
   }
  }
 
  // 获得WebContext实例
  WebContext wctx = WebContextFactory.get();
  // 获得当前页面的Util实例，用以***作当前页面的HTML元素
  Util utilThis = new Util(wctx.getScriptSession());
  // 清除输入文本框的内容
  utilThis.setValue("text","");
  String currentPage = wctx.getCurrentPage();
  Collection sessions = wctx.getScriptSessionsByPage(currentPage);
  Util utilAll = new Util(sessions);
  // 将所有页面中的charlog的所有元素删除
  utilAll.removeAllOptions("charlog");
  // 将messages中的元素的text属性添加成选项
  utilAll.addOptions("Charlog",messages,"text");
}
}
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| DWR2.1 API Doc
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