Flex与Java的简易消息推送机制举例-
Flex与Java的简易消息推送机制举例
使用adobe提供的java flex通信包blazeDS中提供的推送功能实现Java到Flex的数据推送过程
1. 从adobe官网下载blazeds.war,这是一个压缩包,里面的包含META-INF和WEB-INF两个文件夹,目录结构如下:其中含META-INF仅包含MANIFEST.MF文件, WEB-INF中包含classes、flex、lib及src四个文件夹，其中flex文件夹中包含四个配置文件，lib中包含java和flex通讯所需要的jar包。
Flex文件夹中包含：
Lib文件夹包含：
2. 创建Java后台的推送服务项目
新建一个DynamicWeb Project,如:JavaPushServer
点击Next
点击Next
点击Finish,这时候创建了一个空的动态web项目,使用Tomcat6运行.这时候Eclipse中的见到的项目信息如下:Java Resources中的src为java源代码,Libraries中为java运行所依赖的jar包,如果已经配置好了Tomcat运行环境,则Apache Tomcat v6.0…目录下自动加载了Tomcat的jar包,和JRE System Library目录下的jar包
因为通讯需要blazeds,所以,这时候,可以将blazeds.war解压出来的两个文件夹替换掉刚才创建的web工程中WebContent文件目录下的内容.替换之后可以看到WebContent文件夹下内容变化情况:
以及Java Sources中的Libraries中Web App Libraries中增加了很多jar包,这些就是blazeds.war中所包含的jar包
引入blazeds.war之后,开始写Java代码:
创建名为Tick的java实体类:
package com.eunut.vo;
//实体类
public class Tick {
privateString seqno;
publicString getSeqno(){
returnseqno;
}
//字符类型,为测试用仅仅加了一个属性,可以为多个
publicvoid setSeqno(String seqno)
{
this.seqno=seqno;
}
}
然后再创建一个名为TickCacheServlet的Servlet
举例代码如下:
import java.io.IOException;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
import com.eunut.vo.Tick;
importflex.messaging.MessageBroker;
importflex.messaging.messages.AsyncMessage;
importflex.messaging.util.UUIDUtils;
/**
* Servlet implementation classTickCacheServlet
*/
public class TickCacheServletextends HttpServlet {
privatestatic final long serialVersionUID = 1L;
//线程
privatestatic FeedThread thread;
/**
* @see HttpServlet#HttpServlet()
*/
public TickCacheServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequestrequest, HttpServletResponse response)
*/
protectedvoid doGet(HttpServletRequest request, HttpServletResponse response) throwsServletException, IOException {
//TODO Auto-generated method stub
Stringcmd=request.getParameter("cmd");
if(cmd.equals("start"))
{
start();
}
if(cmd.equals("stop"))
{
stop();
}
}
/**
* @see HttpServlet#doPost(HttpServletRequestrequest, HttpServletResponse response)
*/
protectedvoid doPost(HttpServletRequest request, HttpServletResponse response) throwsServletException, IOException {
//TODO Auto-generated method stub
super.doPost(request,response);
}
//初始化
publicvoid init() throws ServletException{
super.init();
}
publicvoid destroy(){
super.destroy();
}
//启动监听
publicvoid start(){
if(thread==null)
{
thread=newFeedThread();
thread.start();
}
System.out.println("start!!!");
}
//停止监听
publicvoid stop(){
thread.running=false;
thread=null;
}
//循环发送消息进程
publicstatic class FeedThread extends Thread
{
publicboolean running=true;
publicvoid run(){
//总是无法获取msgBroker,web.xml需要有MessageBrokerServlet的配置信息
MessageBrokermsgBroker=MessageBroker.getMessageBroker(null);
StringclientID=UUIDUtils.createUUID();
inti=0;
while(running){
Ticktick=new Tick();
tick.setSeqno(String.valueOf(i));
System.out.println(i);
AsyncMessagemsg=new AsyncMessage();
msg.setDestination("tick-data-feed");
msg.setHeader(AsyncMessage.SUBTOPIC_HEADER_NAME,"tick");
msg.setClientId(clientID);
msg.setMessageId(UUIDUtils.createUUID());
msg.setTimestamp(System.currentTimeMillis());
msg.setBody(tick);
msgBroker.routeMessageToService(msg,null);
i++;
try
{
Thread.sleep(2000);
}
catch(InterruptedExceptione)
{
}
}
}
}
}
3. 修改Java后台的推送服务项目的配置文件:
WebContent\WEB-INF\messaging-config.xml
<?xml version="1.0"encoding="UTF-8"?>
<serviceid="message-service"
class="flex.messaging.services.MessageService">
<adapters>
<adapter-definitionid="actionscript"class="flex.messaging.services.messaging.adapters.ActionScriptAdapter"default="true" />
<!-- <adapter-definitionid="jms"class="flex.messaging.services.messaging.adapters.JMSAdapter"/>-->
</adapters>
<default-channels>
<channelref="my-polling-amf"/>
</default-channels>
<!-- 增加配置信息 -->
<destination id="tick-data-feed">
<properties>
<server>
<allow-subtopics>true</allow-subtopics>
<subtopic-separator>.</subtopic-separator>
</server>
</properties>
<channels>
<channel ref="my-polling-amf" />
<channel ref="my-streaming-amf" />
</channels>
</destination>
</service>
以及services-config.xml中补充:
<!-- 补充my-streaming-amf通道配置信息 -->
<channel-definitionid="my-streaming-amf"class="mx.messaging.channels.StreamingAMFChannel">
<endpointurl="http://{server.name}:{server.port}/{context.root}/messagebroker/streamingamf"class="flex.messaging.endpoints.StreamingAMFEndpoint"/>
<properties>
<idle-timeout-minutes>0</idle-timeout-minutes>
<max-streaming-clients>10</max-streaming-clients>
<server-to-client-heartbeat-millis>5000</server-to-client-heartbeat-millis>
<user-agent-settings>
<user-agent match-on="MSIE"kickstart-bytes="2048"max-streaming-connections-per-session="1"/>
<user-agentmatch-on="Firefox" kickstart-bytes="2048"max-streaming-connections-per-session="1"/>
</user-agent-settings>
</properties>
</channel-definition>
同时,还要确保web.xml中包含下面的内容:
<!-- MessageBroker Servlet-必须的,否则获取不到MessageBrokerServlet,无法发送消息 -->
<servlet>
<servlet-name>MessageBrokerServlet</servlet-name>
<display-name>MessageBrokerServlet</display-name>
<servlet-class>flex.messaging.MessageBrokerServlet</servlet-class>
<init-param>
<param-name>services.configuration.file</param-name>
<param-value>/WEB-INF/flex/services-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>MessageBrokerServlet</servlet-name>
<url-pattern>/messagebroker/*</url-pattern>
</servlet-mapping>
<!-- 下面的是自动生成的 -->
<servlet>
<javaee:description></javaee:description>
<javaee:display-name>TickCacheServlet</javaee:display-name>
<servlet-name>TickCacheServlet</servlet-name>
<servlet-class>TickCacheServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>TickCacheServlet</servlet-name>
<url-pattern>/TickCacheServlet</url-pattern>
</servlet-mapping>
4. 创建Flex客户端应用程序FlexPushClient.mxml:
<?xml version="1.0"encoding="utf-8"?>
<s:Applicationxmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"minWidth="955" minHeight="600">
<fx:Declarations>
<!--将非可视元素（例如服务、值对象）放在此处 -->
</fx:Declarations>
<fx:Script>
<![CDATA[
importcom.eunut.Tick;
importmx.controls.Alert;
importmx.messaging.ChannelSet;
importmx.messaging.Consumer;
importmx.messaging.channels.StreamingAMFChannel;
importmx.messaging.events.ChannelEvent;
importmx.messaging.events.MessageEvent;
[Bindable]
publicvar tick:Tick;
publicfunction submsg():void
{
varconsumer:Consumer=new Consumer();
consumer.destination="tick-data-feed";
consumer.subtopic="tick";
consumer.addEventListener(MessageEvent.MESSAGE,messageHandler);
varurl:String ="http://localhost:8080/JavaPushServer/";
varmyStreamingAMF:StreamingAMFChannel = newStreamingAMFChannel(url+"my-streaming-amf",url+"messagebroker/streamingamf");
varchannelSet:ChannelSet = new ChannelSet();
channelSet.addChannel(myStreamingAMF);
consumer.channelSet= channelSet;
// consumer.channelSet = newChannelSet(["my-streaming-amf"]);
consumer.subscribe(); //开始接收
Alert.show("消费者初始化完毕！");
}
privatefunction messageHandler(event:MessageEvent):void
{
vartick:Tick = event.message.body as Tick;
txtTick.text= tick.seqno;
}
]]>
</fx:Script>
<mx:Panelx="24" y="35" width="362" height="302"layout="absolute" title="Watch Tick">
<mx:Labelx="72" y="43" text="Label"id="txtTick"/>
<mx:Buttonx="132" y="41" label="Button"click="submsg()"/>
</mx:Panel>
</s:Application>
还要创建Tick的as类:
package com.eunut
{
importmx.rpc.remoting.RemoteObject;
[RemoteClass(alias="com.eunut.vo.Tick")] //用于和java后台类转换alias为java类的命名空间,否则不能转换
[Bindable]
publicclass Tick
{
publicfunction Tick()
{
}
publicvar seqno:String;
}
}
配置此flex的应用程序的服务器为刚才创建好的JavaPushServer
好了,这样就可以了哦,现在就是如果看到推送的效果了,启动方式如下:
首先运行发布到Tomcat上的JavaPushServer,然后,打开客户端网址: http://localhost:8080/JavaPushServer/FlexPushClient.html
这时候显示的界面如下:
此时,点击Button按钮,启动监听程序.
然后,需要启动服务器端的监听:
http://localhost:8080/JavaPushServer/TickCacheServlet?cmd=start
如果一切顺利,则可以看到Label显示的数字从0开始逐个增加.
通过调用:
http://localhost:8080/JavaPushServer/TickCacheServlet?cmd=stop
就关闭服务器端的监听程序
注意:途中可能出现这样那样的问题,绝大部分都是因为配置文件不正确引起的,所以,遇到问题时,一定要仔细查看配置文件中的内容是否正确.
