使用pushlet实现消息服务端推送至客户端

1、基础概念：Pushlet是一种comet实现：在Servlet机制下，数据从server端的Java对象直接推送（push）到（动态）HTML页面，而无需任何Java applet或者插件的帮助。

2、一个简单的demo：

1）导入所需要的jar包：pushlet.jar

2）将配置文件pushlet.properties、sources.properties导入到src目录下

pushlet.properties：

config.version=1.0.2
controller.class=nl.justobjects.pushlet.core.Controller
dispatcher.class=nl.justobjects.pushlet.core.Dispatcher
logger.class=nl.justobjects.pushlet.util.Log4jLogger
sessionmanager.class=nl.justobjects.pushlet.core.SessionManager
session.class=nl.justobjects.pushlet.core.Session
subscriber.class=nl.justobjects.pushlet.core.Subscriber
subscription.class=nl.justobjects.pushlet.core.Subscription
log.level=4
sources.activate=true
session.id.generation=randomstring
session.timeout.mins=5
queue.size=24
queue.read.timeout.millis=20000
queue.write.timeout.millis=20
listen.force.pull.all=false
listen.force.pull.agents=safari
pull.refresh.timeout.millis=45000
pull.refresh.wait.min.millis=2000
pull.refresh.wait.max.millis=6000
poll.refresh.timeout.millis=60000
poll.refresh.wait.min.millis=6000
poll.refresh.wait.max.millis=10000

source.properties:

source6=cn.ffcs.pushmessage.plushlet.MessagePlushlet$Plushlet

3）修改web.xml文件如下（url-pattern暂时设置为/pushlet.srv）

Xml代码  

1. <servlet-name>pushlet</servlet-name>  
2.     <servlet-class>nl.justobjects.pushlet.servlet.Pushlet</servlet-class>  
3.     <load-on-startup>1</load-on-startup>  
4. </servlet>  
5. <servlet-mapping>  
6.     <servlet-name>pushlet</servlet-name>  
7.     <url-pattern>/pushlet.srv</url-pattern>  
8. </servlet-mapping>  

   4)编写一个java类如下

Java代码  

 

package cn.ffcs.pushmessage.plushlet;import java.io.Serializable;import nl.justobjects.pushlet.core.Event;import nl.justobjects.pushlet.core.EventPullSource;import nl.justobjects.pushlet.core.Session;import nl.justobjects.pushlet.core.SessionManager;import org.springframework.beans.BeansException;import org.springframework.beans.factory.BeanFactory;import org.springframework.beans.factory.BeanFactoryAware;import cn.ffcs.pushmessage.domain.PushMessage;import cn.ffcs.pushmessage.service.api.IPushMessageService;@SuppressWarnings("serial")public class MessagePlushlet implements Serializable, BeanFactoryAware{private IPushMessageService pushMessageService;public static class Plushlet extends EventPullSource{/** * 设置休眠时间 */@Overrideprotected long getSleepTime() {return 4000;}/**     * 创建事件     *      * 业务部分写在pullEvent()方法中，这个方法会被定时调用。     */@Overrideprotected Event pullEvent() {Event event = Event.createDataEvent("/message/plushlet");IPushMessageService pushMessageService = (IPushMessageService) getBean("cn.ffcs.pushmessage.service.impl.PushMessageServiceImpl");PushMessage pushMessage = pushMessageService.getById(1);System.out.println(event.getField("p_id") + "==================");System.out.println(event.getField("userId") + "==================");System.out.println(event.getField("p_format") + "==================");System.out.println(event.getSubject());Session[] sessions = SessionManager.getInstance().getSessions(); //sessions[0].getEvent().getField("userId");System.out.println(sessions[0].getEvent().getField("userId"));event.setField("id", "1");return event;}}public IPushMessageService getPushMessageService() {return pushMessageService;}public void setPushMessageService(IPushMessageService pushMessageService) {this.pushMessageService = pushMessageService;}private static BeanFactory beanFactory;          public static Object getBean(String beanName) {           return beanFactory.getBean(beanName);      }            public static <T> T getBean(String beanName, Class<T> clazs) {           return clazs.cast(getBean(beanName));      }            @SuppressWarnings("static-access")public void setBeanFactory(BeanFactory beanFactory) throws BeansException {      this.beanFactory = beanFactory;      }}

   还有就是注意Event event = Event.createDataEvent("/message/plushlet");// 事件标识

 

5)编写jsp文件如下<%@ page language="java" contentType="text/html; charset=UTF-8"

Java代码  

1.     <script type="text/javascript" src="/scripts/jquery.min.js"></script>
   <script type="text/javascript" src="/scripts/ajax-pushlet-client.js"></script>
   <script src="/scripts/yanue.pop.js"  type="text/javascript"></script>
   <script type="text/javascript" src="/scripts/jquery.jplayer.min.js"></script>
   <script type="text/javascript"> 
   
           //对pushlet的初始化，触发web.xml中的servlet。
           PL._init(); 
           //这里的监听的主题，必须在sources.properties中配置的对象中声明这个主题。
           //sources.properties配置着事件源（EventSources），在服务器启动时会自动激活。
           //可以通过服务器的启动记录查看得到。可以将这个文件放到WEB-INF目录下面或者classess目录下面都可以。
           //PL.parameters.push({"userId":"1", "value":"4214f0c0da6760a9e95e3c164998ac06"});  
           PL.joinListen('/message/plushlet'); 
           function onData(event) {
           //alert('123'); 
           //event.setField("userId","123");
           var pop=new Pop("这里是标题，哈哈",
           "http://www.yanue.info/js/pop/pop.html",
           "请输入你的内容简介，这里是内容简介.请输入你的内容简介，这里是内容简介.请输入你的内容简介，这里是内容简介");
               
               getRingData();
           } 
           //onData();
           
            function getRingData(){
           //alert('123');
      var attachmentUrl = "http://localhost:8080/upload/ring/1394107276542.mp3";
      $('#jqDiv div').remove();    //将jplayer渲染的div层移除后重新添加，不然jplayer只会播放一次
   $('#jqDiv').append('<div id="jquery_jplayer_1" class="jp-jplayer" style="width:500px;"></div>');
   $("#jquery_jplayer_1").jPlayer("stop");
   $("#jquery_jplayer_1").jPlayer({
   ready: function (event) {
   $(this).jPlayer("setMedia", {
   mp3:attachmentUrl
   }).jPlayer("play");
   },
   swfPath: "js",
   supplied: "m4a, oga, mkv, mp3, mp4",
   wmode: "window"
   });
   }
           
   </script>

<div id="jqDiv">
<div id="jquery_jplayer_1" class="jp-jplayer" style="width:500px;"></div>
</div>

1.  

   PL.joinListen('/message/plushlet');//事件标识 在数据源中引用，注意跟上面的红色部分保持一致。

   调用getRingData()为弹窗显示后的声音提醒。

<body><div id="pop" style="display:none;"><style type="text/css">*{margin:0;padding:0;}#pop{background:#fff;width:260px;border:1px solid #e0e0e0;font-size:12px;position: fixed;right:10px;bottom:10px;}#popHead{line-height:32px;background:#f6f0f3;border-bottom:1px solid #e0e0e0;position:relative;font-size:12px;padding:0 0 0 10px;}#popHead h2{font-size:14px;color:#666;line-height:32px;height:32px;}#popHead #popClose{position:absolute;right:10px;top:1px;}#popHead a#popClose:hover{color:#f00;cursor:pointer;}#popContent{padding:5px 10px;}#popTitle a{line-height:24px;font-size:14px;font-family:'微软雅黑';color:#333;font-weight:bold;text-decoration:none;}#popTitle a:hover{color:#f60;}#popIntro{text-indent:24px;line-height:160%;margin:5px 0;color:#666;}#popMore{text-align:right;border-top:1px dotted #ccc;line-height:24px;margin:8px 0 0 0;}#popMore a{color:#f60;}#popMore a:hover{color:#f00;}</style><div id="popHead"><a id="popClose" title="关闭">关闭</a><h2>温馨提示</h2></div><div id="popContent"><dl><dt id="popTitle"><a href="http://yanue.info/" target="_blank">这里是参数</a></dt><dd id="popIntro">这里是内容简介</dd></dl><p id="popMore"><a href="http://yanue.info/" target="_blank">查看 »</a></p></div></div><div id="jquery_jplayer_1"></div></body>

6）下面说一下web.xml中<url-pattern>的配置问题,查看ajax-pushlet-client.js源码会发现有下面这段代码_getWebRoot: function() {

Js代码  

1.     /** Return directory of this relative to document URL. */  
2.     if (PL.webRoot != null) {  
3.         return PL.webRoot;  
4.     }  
5.     //derive the baseDir value by looking for the script tag that loaded this file  
6.     var head = document.getElementsByTagName('head')[0];  
7.     var nodes = head.childNodes;  
8.     for (var i = 0; i < nodes.length; ++i) {  
9.         var src = nodes.item(i).src;  
10.         if (src) {  
11.             var index = src.indexOf("lib/ajax-pushlet-client.js");  
12.             if (index >= 0) {  
13.                 PL.webRoot = src.substring(0, index);  
14.                 break;  
15.             }  
16.         }  
17.     }  
18.     return PL.webRoot;  
19. },  

 注意var index = src.indexOf("lib/ajax-pushlet-client.js");这句话 这个方法就是取webRoot跟路径的，所以<url-pattern>的设置跟这里有关系，还有就是跟你使用ajax-pushlet-client.js的jsp页面有关系，我上面的jsp页面中src="js/ajax-pushlet-client.js"是这样导入js包的，所以我把ajax-pushlet-client.js中的代码改为var index = src.indexOf("js/ajax-pushlet-client.js");取根路径了。