2010.04.09(3)———dwr群聊

2010.04.09(3)———dwr群聊


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">
  	<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
    <!-- 以设置下格式固定，可复制使用 -->  
    <display-name>ajaxDWR</display-name>  
    <servlet>  
        <servlet-name>dwr-invoker</servlet-name> 
        <servlet-class>  
            org.directwebremoting.servlet.DwrServlet   
        </servlet-class>  
        <init-param>  
            <description>实现调试，在debug请设置为false</description>  
            <param-name>debug</param-name>  
            <param-value>true</param-value>  
        </init-param>  
        <init-param>  
            <description>使用服务器推技术(反转AJAX)</description>  
            <param-name>activeReverseAjaxEnabled</param-name>  
            <param-value>true</param-value>  
        </init-param>  
        <init-param>  
            <param-name>  
                initApplicationScopeCreatorsAtStartup   
            </param-name>  
            <param-value>true</param-value>  
        </init-param>  
        <init-param>  
            <param-name>maxWaitAfterWrite</param-name>  
            <param-value>100</param-value>  
        </init-param>  
        <load-on-startup>4</load-on-startup>  
    </servlet>  
    <servlet-mapping>  
        <servlet-name>dwr-invoker</servlet-name>  
        <url-pattern>/dwr/*</url-pattern>  
    </servlet-mapping>  
  
</web-app>  

java

package dwr;
import java.util.ArrayList;   
import java.util.Collection;   
  
import javax.servlet.ServletContext;   
import javax.servlet.http.HttpServletRequest;   
  
import org.directwebremoting.ServerContext;   
import org.directwebremoting.ServerContextFactory;   
import org.directwebremoting.proxy.dwr.Util; 
public class Chat {   
    static ArrayList<String> name_list = new ArrayList<String>();   
    static StringBuffer show_message = new StringBuffer();    
  
    public String addUser(String name,HttpServletRequest request) {   
        System.out.println("list.size() = "+name_list.size());   
        for (String s : name_list) {   
            if (name == null || name.trim().equals(s)) {   
                return "用户名已存在";   
            }     
        }   
        name_list.add(name.trim());
        
        ServletContext sc = request.getSession().getServletContext();
        //获得DWR上下文 
        ServerContext sctx = ServerContextFactory.get(sc);   
        //获得当前浏览 某页面 已开启的所有脚本session
        //页面地址，以工程同目录真实地址为准，如：/部署名/pages/index.jsp 
        Collection sessions = sctx.getScriptSessionsByPage("/chat/index.jsp");   
        Util util = new Util(sessions);   
        show_message.append("\n欢迎"+name+"来到 XXX Chat");   
        trimMessage();   
        util.setValue("showmessage", show_message.toString());   
        printUserList(util);   
        return "";   
    }   
       
    public void sayMessage(String message,HttpServletRequest request){   
        ServletContext sc = request.getSession().getServletContext();   
        ServerContext sctx = ServerContextFactory.get(sc);   
        Collection sessions = sctx.getScriptSessionsByPage("/chat/index.jsp");   
        Util util = new Util(sessions);   
        show_message.append("\n"+message);   
        trimMessage();   
        util.setValue("showmessage", show_message.toString());   
        printUserList(util);   
    }   
       
    public void trimMessage(){   
        if(show_message.length() > 2000){   
            show_message.delete(0, ((show_message.length() - 2000)*2+2));   
        }   
    }   
       
    public void printUserList(Util util){   
        StringBuffer userlist = new StringBuffer();   
        userlist.append("<table>");   
        for(String s : name_list){   
            userlist.append("<tr><td><font color='blue'>"+s+"</font></td></tr>");   
        }   
        userlist.append("</table>");   
        util.setValue("userlist", userlist.toString());   
    }   
}  

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>  
    <!-- 对后台类的配置格式确定 -->  
    <allow>          
        <create creator="new" javascript="Chat">  
            <param name="class" value="dwr.Chat" />  
        </create>  
    </allow>  
</dwr>  

jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>  
    <head>  
        <title>群聊</title>  
  
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  
        <meta http-equiv="description" content="this is my page">  
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">  
        <script type='text/javascript' src='dwr/util.js'></script>  
        <script type='text/javascript' src='dwr/engine.js'></script>  
        <script type='text/javascript' src='dwr/interface/Chat.js'></script>  
        <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->  
  
    </head>  
  
    <body>  
        <center>  
            <table width="600px" border="1">  
                <tr>  
                    <td colspan="3" align="center">  
                        XXXXXX Chat   
                    </td>  
                    <td>  
                        User List   
                    </td>  
                </tr>  
                <tr>  
                    <td colspan="3" style="height: 300px">  
                        <textarea rows="20" cols="60" readonly="readonly" id="showmessage" name="showmessage"></textarea>  
                    </td>  
                    <td style="height: 300px"  valign="top">  
                        <div id="userlist" style="height:310px;overflow : scroll;"></div>  
                    </td>  
                </tr>  
                <tr>  
                    <td colspan="3" align="center">  
                        <span id="say_name" ></span>  
                        <textarea rows="3" cols="50" id="say_message" name="say_message" ></textarea><input type="button" value="say" id="say" onclick="sayMessage()"/>  
                    </td>  
                    <td>  
                        先录入你的昵称<br/>  
                        <input type="text" style="width: 125px" name="name" id="name" />  
                        <input type="button" value="确定" onclick="register()" />  
                    </td>  
                </tr>  
            </table>  
        </center>  
    </body>  
    <script type="text/javascript">  
        dwr.engine.setActiveReverseAjax(true); // 激活反转 重要   
           
        init();   
           
        function init(){   
            document.getElementById('say_message').disabled = true;   
            document.getElementById('say').disabled = true;   
        }   
           
        function sayMessage(){   
            var message_content = DWRUtil.getValue('say_message');   
            var message_head = document.getElementById('say_name').innerHTML;   
            Chat.sayMessage(message_head+message_content);   
            document.getElementById('say_message').value = '';   
        }   
           
        function register() {   
            var name = DWRUtil.getValue("name");   
            Chat.addUser(name,callback);   
        }   
           
        function callback(str) {   
            if(str != ''){   
                alert(str);   
            }else{   
                document.getElementById('say_name').innerHTML = DWRUtil.getValue("name") + " 说：";   
                document.getElementById('say_message').disabled = false;   
                document.getElementById('say').disabled = false;   
            }      
        }   
    </script>  
</html>