DWR+jedis订阅发布demo

ZZMWXH

于 2018-05-07 14:30:35 发布

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分类专栏：自创+借鉴文章标签： dwr jedis订阅发布

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4 篇文章

订阅专栏

本文介绍如何使用 DWR 和 Redis 在 Java Web 应用中实现消息的发布订阅功能。具体步骤包括配置 Maven 依赖、Web 配置文件、创建 DWR 交互类、实现消息处理逻辑等。

整个demo步骤如下：

（1）由于项目是maven项目，需配置pom.xml下载jedis和dwr。如果是普通的web项目，自行下载jar包

             <!-- jedis -->
		<dependency>
			<groupId>redis.clients</groupId>
			<artifactId>jedis</artifactId>
			<version>2.8.0</version>
		</dependency>
		<!-- dwr -->
		<dependency>
			<groupId>org.directwebremoting</groupId>
			<artifactId>dwr</artifactId>
			<version>3.0.2-RELEASE</version>
		</dependency>

（2）配置web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
 http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
	version="3.1" metadata-complete="true">
	<!-- 如果是用mvn命令生成的xml，需要修改servlet版本为3.1 -->
	<!-- 配置DispatcherServlet -->
	<servlet-mapping>
		<servlet-name>default</servlet-name>
		<url-pattern>*.js</url-pattern>
	</servlet-mapping>
	<servlet-mapping>
		<servlet-name>default</servlet-name>
		<url-pattern>*.css</url-pattern>
	</servlet-mapping>
	<!-- DWR服务器推技术 -->
	<servlet>
		<servlet-name>dwr-invoker</servlet-name>
		<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
		<init-param>  
      <param-name >org.directwebremoting.extend.ScriptSessionManager </param-name>  
      <param-value >com.demo1.dwr.DWRScriptSessionManager </param-value>  
     </init-param>  
		<init-param>
     		<param-name>debug</param-name>
    		<param-value>true</param-value>
  		</init-param>
  		 <init-param>  
  		  <!-- comet方式 -->  
            <param-name>activeReverseAjaxEnabled</param-name>  
            <param-value>true</param-value>  
        </init-param>  
        <init-param>
             <param-name>crossDomainSessionSecurity</param-name>
             <param-value>false</param-value>
      </init-param>
      <init-param>
            <param-name>allowScriptTagRemoting</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>
</web-app>

（3）新建一个dwr.xml，必须与web,xml在同一级目录下，其中value是对应的java类，稍后在后边会有代码

<!DOCTYPE dwr PUBLIC
          "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN"
          "http://getahead.org/dwr/dwr30.dtd">

<dwr>
	<allow>
		<create creator="new" javascript="MessagePush">
			<param name="class" value="com.demo1.dwr.MessagePush" />
		</create>
		<create creator="new" javascript="JedisPubSubMessage">
			<param name="class" value="com.demo1.jedis.JedisPubSubMessage" />
		</create>


	</allow>
</dwr>

（4）MessagePush类,在这个类中，改成自己要连的jedis服务器

package com.demo1.dwr;

import javax.servlet.ServletException;

import org.directwebremoting.ScriptSession;
import org.directwebremoting.WebContextFactory;

import com.demo1.jedis.JedisPubSubMessage1;

import redis.clients.jedis.Jedis;

public class MessagePush{
	
         //订阅频道
	public void subTest(final String channel){
		final Jedis jedis=new Jedis("172.16.239.10",6379);
		jedis.auth("wxh");
		ScriptSession scriptsession =WebContextFactory.get().getScriptSession();
		scriptsession.setAttribute("sub","true");
		scriptsession.setAttribute("subname",channel);
   		 final JedisPubSubMessage1   jsm  = new JedisPubSubMessage1();
   	 //   jedis.subscribe(jsm, channel);
   	       Thread t=	 new Thread(new Runnable(){
   		    public void run(){
   		     jedis.subscribe(jsm, channel);
   		    }
   		 });
   	   t.start();
	}
      //发布消息
	public void pubTest(String channel,String message){
		Jedis jedis=new Jedis("172.16.239.10",6379);
		jedis.auth("wxh");
		jedis.publish(channel, message);
	}
}

(5) jedisPubSubMessage

package com.demo1.jedis;
import java.util.Collection;
import org.directwebremoting.Browser;
import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.ScriptSessionFilter;
import org.directwebremoting.ScriptSessions;
import org.directwebremoting.ServerContextFactory;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;

import com.demo1.dwr.DWRScriptSessionListener;

import redis.clients.jedis.JedisPubSub;
/**
 * *******消息订阅处理类*******
 * @author Administrator
 *
 */
public class JedisPubSubMessage extends JedisPubSub {
	// 监听到订阅频道接受到消息时的回调 (onMessage )
	@Override
	public void onMessage(String channel, String message) {
		//接收订阅频道消息后，业务处理逻辑
		//super.onMessage(channel, message);
		//System.out.println("通道为: "+channel+"   "+"监听意见被通知,收到的消息为:"+message);
		final String Msg=message;
		final String cha=channel;
		System.out.println("channel是:"+cha);
		Browser.withAllSessionsFiltered(new ScriptSessionFilter() {
			public boolean match(ScriptSession session) {
			if(("true").equals(session.getAttribute("sub"))&&(cha.equals(session.getAttribute("subname")))){
				//if(session.getAttribute("sub")=="true"){
					return true;
				}
				return false;
			}  
		}, new Runnable(){  
			private ScriptBuffer script = new ScriptBuffer();  
			public void run(){  
				//推送消息
				script.appendCall("showMsg",Msg); 
				//得到所有ScriptSession
	         Collection<ScriptSession> sessions = Browser.getTargetSessions();  
				//Collection<ScriptSession> sessions = DWRScriptSessionListener.getScriptSessions();  
				for (ScriptSession scriptSession : sessions){ 
					System.out.println("接收消息成功");
					//添加待执行的脚本到dwr excution池中
					scriptSession.addScript(script);  
				}  
			}  
		});  
	}
// 订阅频道模式时的回调 ( onPSubscribe )
@Override
public void onSubscribe(String channel, int subscribedChannels) {
	// TODO Auto-generated method stub
	//super.onSubscribe(channel, subscribedChannels);
	System.out.println(" >> 开始订阅  频道,订阅的频道为: "+channel);
	final String chan=channel;
	Browser.withAllSessionsFiltered(new ScriptSessionFilter() {
		public boolean match(ScriptSession session) {
			if(("true").equals(session.getAttribute("sub"))){
			    return true;
			}else{
				return false;
			}
		}  
	}, new Runnable(){  
		private ScriptBuffer script = new ScriptBuffer();  
		public void run(){  
			//推送消息
			script.appendCall("showchan",chan); 
			//得到所有ScriptSession
			Collection<ScriptSession> sessions = Browser.getTargetSessions();  
			for (ScriptSession scriptSession : sessions){ 
				System.out.println("订阅频道成功");
				//添加待执行的脚本到dwr excution池中
				scriptSession.addScript(script);  
			}  
		}  
	});  
}
}

（6）新建一个dwrsub.jsp，此页面主要实现订阅功能。

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>  
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">  
<html>  
  <head>  
  <%  
    String path = request.getContextPath();  
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";  
%>  
<base href="<%=basePath%>"> 
  </head>  
  <script type='text/javascript' src='dwr/engine.js'></script>  
  <script type='text/javascript' src='dwr/util.js'></script>  
  <script type="text/javascript" src="dwr/interface/MessagePush.js"></script>  
  <script src="http://code.jquery.com/jquery-latest.js"></script>
  <script type="text/javascript" src="dwr/interface/JedisPubSubMessage.js"></script>  
   <script type="text/javascript" src="dwr/interface/JedisPubSubMessage1.js"></script>  
  <script type="text/javascript">  
        function showMsg(Msg){ 
        	alert("消息接收成功");
          $("#msg").val(Msg);
        }  
      /*   function test1() {
        	JedisPubSubMessage.onMessage("ss","ss1");
    	} */
        function sub(){
    		var cha=$("#channe").val();
        	MessagePush.subTest(cha);
        }
    	 function showchan(chan){ 
    	alert("订阅成功");
    }
  </script>  
  <body onload="dwr.engine.setActiveReverseAjax(true);dwr.engine.setNotifyServerOnPageUnload(true);;"> 
                频道： <input type="text" id="channe" >
     <input type="button" onclick="sub()" value="订阅"><br/>
              频道收到到的消息： <input type="text" id="msg">
  </body>  
</html>

注意:

  //这个方法用来启动该页面的ReverseAjax功能
         dwr.engine.setActiveReverseAjax( true);
         //设置在页面关闭时，通知服务端销毁会话
         dwr.engine.setNotifyServerOnPageUnload( true);

(7)新建一个dwrpub.jsp,此页面主要实现发布功能

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>  
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">  
<html>  
  <head>  
  <%  
    String path = request.getContextPath();  
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";  
      
%>  
<base href="<%=basePath%>"> 
  </head>  
  <script type='text/javascript' src='dwr/engine.js'></script>  
  <script type='text/javascript' src='dwr/util.js'></script>  
  <script type="text/javascript" src="dwr/interface/MessagePush.js"></script>  
  <script src="http://code.jquery.com/jquery-latest.js"></script>
  <script type="text/javascript" src="dwr/interface/JedisPubSubMessage.js"></script>  
   <script type="text/javascript" src="dwr/interface/JedisPubSubMessage1.js"></script>  
  <script type="text/javascript">  
        function pub(){
        	var ch=$("#chan1").val()
        	var ms=$("#message").val();
        	MessagePush.pubTest(ch,ms);
        }
     /*    function showchan(chan){ 
        	alert("频道接收成功");
           $("#chan1").val(chan);
        }   */
  </script>  
   <body onload="dwr.engine.setActiveReverseAjax(true);dwr.engine.setNotifyServerOnPageUnload(true);;">
   <!-- <body> -->          
               频道: <input type="text" id="chan1">
                 消息： <input type="text" id="message" >
     <input type="button" onclick="pub()" value="发布">
  </body>  
</html>

完成这几步，访问这两个页面就能实现dwr+发布订阅的功能了。注意在运行此代码时，记得启动redis服务器。