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）

 <servlet-name>pushletservlet-name>
     <servlet-class>nl.justobjects.pushlet.servlet.Pushletservlet-class>
     <load-on-startup>1load-on-startup>
 servlet>
 <servlet-mapping>
     <servlet-name>pushletservlet-name>
     <url-pattern>/pushlet.srvurl-pattern>
 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
		 */
		@Override
		protected 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。
	     */
		@Override
		protected 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 getBean(String beanName, Class 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"

      </span><br><span style="color:#2b91af;"><span></span></span><br><span style="color:#2b91af;">        //对pushlet的初始化，触发web.xml中的servlet。</span><br><span style="color:#2b91af;">        PL._init(); </span><br><span style="color:#2b91af;">        //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。</span><br><span style="color:#2b91af;">        //sources.properties配置着事件源（EventSources），在服务器启动时会自动激活。</span><br><span style="color:#2b91af;">        //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。</span><br><span style="color:#2b91af;">        //PL.parameters.push({"userId":"1", "value":"4214f0c0da6760a9e95e3c164998ac06"});  </span><br><span style="color:#2b91af;">        PL.joinListen('/message/plushlet'); </span><br><span style="color:#2b91af;">        function onData(event) {</span><br><span style="color:#2b91af;">        <span></span>//alert('123'); </span><br><span style="color:#2b91af;">        <span></span>//event.setField("userId","123");</span><br><span style="color:#2b91af;">        <span></span>var pop=new Pop("这里是标题，哈哈",</span><br><span style="color:#2b91af;">        <span></span>"http://www.yanue.info/js/pop/pop.html",</span><br><span style="color:#2b91af;">        <span></span>"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");</span><br><span style="color:#2b91af;">            </span><br><span style="color:#2b91af;">            getRingData();</span><br><span style="color:#2b91af;">        } </span><br><span style="color:#2b91af;">        //onData();</span><br><span style="color:#2b91af;">        </span><br><span style="color:#2b91af;">         function getRingData(){</span><br><span style="color:#2b91af;">        </span><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">//alert('123');</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">   var attachmentUrl = "http://localhost:8080/upload/ring/1394107276542.mp3";</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">   $('#jqDiv div').remove();    </span><span style="color:#ff6666;"><strong>//将jplayer渲染的div层移除后重新添加，不然jplayer只会播放一次</strong></span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">$('#jqDiv').append('<div id="jquery_jplayer_1" class="jp-jplayer" style="width:500px;"></div>');</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">$("#jquery_jplayer_1").jPlayer("stop");</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">$("#jquery_jplayer_1").jPlayer({</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">ready: function (event) {</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">$(this).jPlayer("setMedia", {</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">mp3:attachmentUrl</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">}).jPlayer("play");</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">},</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">swfPath: "js",</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">supplied: "m4a, oga, mkv, mp3, mp4",</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">wmode: "window"</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">});</span><br><span style="color:rgb(43,145,175);"></span><span style="color:#2b91af;">}</span><br><span style="color:#2b91af;">        </span><br><span style="color:#2b91af;"><span></span>

   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。

	
	

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

     /** Return directory of this relative to document URL. */
     if (PL.webRoot != null) {
         return PL.webRoot;
     }
     //derive the baseDir value by looking for the script tag that loaded this file
     var head = document.getElementsByTagName('head')[0];
     var nodes = head.childNodes;
     for (var i = 0; i < nodes.length; ++i) {
         var src = nodes.item(i).src;
         if (src) {
             var index = src.indexOf("lib/ajax-pushlet-client.js");
             if (index >= 0) {
                 PL.webRoot = src.substring(0, index);
                 break;
             }
         }
     }
     return PL.webRoot;
 },

 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。