Dwr-推送

[size=large]js代码:(还需要导入dwr的相应js)
[/size]
<script>

window.οnlοad=function(){

//想实现推送 这一句是必需的！！！！！！！！！！！！！！！！！！
dwr.engine.setActiveReverseAjax(true);

$("all").οnclick=function(){

var msg= $("userName").value+"说： "+$("inputText").value;
ChatService.SendMsg(msg);
}
};


//展示消息 后台会调用该方法
var toDisplay=function(msg){
$("show").innerHTML= $("show").innerHTML+"<br/>"+msg;
}

</script>


[size=large]服务器端代码：[/size]

public class ChatService {

//页面调用该方法
public void SendMsg(String msg){
this.Send(msg);
}


//改方法处理后调用页面的方法，从而改变页面
public void Send(String msg){

WebContext ctx = WebContextFactory.get();
String page = ctx.getCurrentPage();
Collection<ScriptSession> sessions = ctx.getScriptSessionsByPage(page);
//确定需要推送给谁
Util util = new Util(sessions);
// 调用js中的toDisplay函数，将msg显示在页面上
util.addFunctionCall("toDisplay", msg);
}
}


[size=large]dwr.xml:[/size]
<?xml version="1.0" encoding="gbk"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "/WEB-INF/dwr10.dtd">
<dwr>
<allow>
<create javascript="ChatService" creator="new">
<param name="class" value="service.ChatService">
</param>
</create>

<create javascript="MoreFunctionChatService" creator="new">
<param name="class" value="service.MoreFunctionChatService">
</param>
</create>

</allow>
</dwr>


[size=large]web.xml需要加:[/size]
<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>

<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>