dwr +spring 实现数据推送

最新推荐文章于 2025-03-10 13:10:13 发布

csgvsjay1000

最新推荐文章于 2025-03-10 13:10:13 发布

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分类专栏：技术积累文章标签： dwr 推送数据

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本文详细介绍了如何利用DWR框架实现反向AJAX功能，通过定义类SendMsg来推送消息，并展示了接收消息的页面配置。此外，文章还涉及到web.xml和dwr.xml的配置，以及消息发送与接收的实现过程。

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dwr是java开发的轻量级框架，主要有两大核心功能：

1：ajax，

2：反ajax。

这篇文章主要介绍dwr的反ajax功能

需要dwr.jar文件，我的版本是3.0

定义一个推送消息的类

package com.alfa.service;

import java.util.Collection;

import org.directwebremoting.Browser;
import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.ScriptSessionFilter;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.proxy.dwr.Util;

public class SendMsg {

	public void send(String msg){
		System.out.println(msg);
		final String autoMsg = msg;
		
		Browser.withPageFiltered("/spring_mvc_010/jms/showMsg.jsp",new ScriptSessionFilter() {
			
			@Override
			public boolean match(ScriptSession arg0) {
				
				return true;
			}
		}, new Runnable() {
			ScriptBuffer sBuffer = new ScriptBuffer();
			@Override
			public void run() {
				sBuffer.appendCall("show", autoMsg);

				Collection<ScriptSession> sessions = Browser.getTargetSessions();

				for (ScriptSession scriptSession : sessions) {
					scriptSession.addScript(sBuffer);
				}		
			}
		});
		
	}
	
}

接收消息页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<c:set var="ctx" value="${pageContext.request.contextPath}" />
<script type="text/javascript" src="${ctx }/js/jquery.js"></script>
<script type="text/javascript" src="${ctx }/dwr/util.js"></script>
<script type="text/javascript" src="${ctx }/dwr/engine.js"></script>
<script type="text/javascript">
  $(function(){
	  
	  dwr.engine.setActiveReverseAjax(true);  
      
  });
 function show(msg){
	 $("#mess").append(msg);
 }
  
 </script>
<title>Insert title here</title>
</head>
<body>
<div id="mess">55</div>
</body>
</html>

发送信息的页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<c:set var="ctx" value="${pageContext.request.contextPath}" />
<script type="text/javascript" src="${ctx }/js/jquery.js"></script>
<script type="text/javascript" src="${ctx }/dwr/util.js"></script>
<script type="text/javascript" src="${ctx }/dwr/engine.js"></script>
<script type="text/javascript" src="${ctx }/dwr/interface/SendMsg.js"></script>
<script type="text/javascript">
  $(function(){
	  
	  dwr.engine.setActiveReverseAjax(true);  

  });
  
  function sendMess(){
	  
	  //SendMsg.send($("#msg").val());
	  
	   $.ajax({
		  type:'POST',
		  url:'${ctx}/user/sendMess.html',
		  success:function(data){
			  alert("邮件已发送！");
		  },
		  error:function(){
			  alert("邮件发送出错！");
		  }
		  
	  }); 
	  
  }

</script>
</head>
<body>
   <input type="text" id="msg"/>
   <input type="submit" value="发送邮件" onclick="sendMess()" />
</body>
</html>

web.xml配置

<servlet>
   <servlet-name>dwr-invoke</servlet-name>
   <servlet-class>uk.ltd.getahead.dwr.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>
   <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dwr-invoke</servlet-name>
    <url-pattern>/dwr/*</url-pattern>
  </servlet-mapping>

dwr.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC 
 "-//GetAhead Limited//DTD Direct Web Remoting 1.0//EN" 
 "http://www.getahead.ltd.uk/dwr/dwr10.dtd">
<dwr>
 <!-- 定义所有需要被暴露的Java方法 --> 
     <allow>
  <!-- 定义将org.apache.struts2.validators.DWRValidator创建成一个validator对象 -->
          <create javascript="SendMsg" creator="spring">
            <param name="beanName" value="sendMsg"></param>
          </create>
     </allow>
     
</dwr>

至于类SendMsg的send方法可以随便调用

接受信息的页面最好是静态页面，我的一个动态页面没接受到，还请知道原因的大师留言哈