Flex之旅--Flex数据推送
本文介绍怎样使用Flex数据推送实现前台消息订阅，是在前面Flex+BlazeDS+Spring整合基础上进行的，利用Spring来简化配置。环境准备：
1.完成Flex+BlazeDS+Spring整合
2.修改项目根目录下.flexProperties文件中serverContextRoot为项目名，否则后台接收不到前台订阅信息(此处浪费了我很多时间，一定注意)
修改配置文件
1.修改WEB-INF/flex/services-config.xml，添加如下代码：
0
10
5000
后台推送数据
1.添加推送数据Service，代码如下，注意msg设置的各参数，前后台及配置文件都要对应
package demo.flex.service;
import javax.annotation.Resource;
import org.springframework.flex.messaging.AsyncMessageCreator;
import org.springframework.flex.messaging.MessageTemplate;
import org.springframework.stereotype.Service;
import flex.messaging.messages.AsyncMessage;
import flex.messaging.util.UUIDUtils;
@Service
public class DataPushService {
@Resource
private MessageTemplate messageTemplate;
public void push(String topic, Object data) {
messageTemplate.send(new CustomAsyncMessageCreator(topic, data));
}
class CustomAsyncMessageCreator implements AsyncMessageCreator {
private String topic;
private Object data;
public CustomAsyncMessageCreator(String topic, Object data) {
this.topic = topic;
this.data = data;
}
@Override
public AsyncMessage createMessage() {
AsyncMessage msg = new AsyncMessage();
msg.setClientId(UUIDUtils.createUUID());
msg.setMessageId(UUIDUtils.createUUID());
msg.setTimestamp(System.currentTimeMillis());
msg.setDestination("data_push"); // 必须和配置文件中message-destination相同
msg.setHeader("DSSubtopic", topic); // 设置订阅主题
msg.setBody(data);
return msg;
}
}
}
2.添加控制数据开始推送及结束推送Controller，每隔一秒推送当前系统时间
package demo.flex.mvc;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.annotation.Resource;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import demo.flex.service.DataPushService;
@Controller
public class DataPush {
private static FeedThread thread;
@Resource
private DataPushService dataPushService;
@RequestMapping("push")
public String push(String cmd) throws Exception {
if ("start".equals(cmd)) {
start();
}
else {
stop();
}
return "push";
}
private void start() {
if (thread == null) {
thread = new FeedThread();
thread.start();
}
System.out.println("开始数据推送...");
}
private void stop() {
thread.running = false;
thread = null;
System.out.println("结束数据推送...");
}
public class FeedThread extends Thread {
public boolean running = true;
private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
public void run() {
while (running) {
String time = sdf.format(new Date());
System.out.println(">>>>>>>>>>>" + time);
// time为订阅主题
dataPushService.push("time", time);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
}
}
}
}
Spring MVC Dispatcher Servlet
/mvc/*
前台订阅功能
前台FlexDemo.mxml中添加如下代码，订阅主题为time的消息，用于显示后台系统时间
private var consumer:Consumer;
protected function showTimeHandler(event:MouseEvent):void
{
if (consumer == null) {
consumer = new Consumer();
// consumer设置的参数要与后台配置对应
consumer.destination = "data_push";
consumer.channelSet = new ChannelSet(["my-streaming-amf","my-polling-amf"]);
// 只能收到主题为time的订阅消息
consumer.subtopic = "time";
//添加message的监听，当后台有消息发送时，调用messageHandler
consumer.addEventListener(MessageEvent.MESSAGE, messageHandler);
// 订阅
consumer.subscribe();
}
}
protected function hideTimeHandler(event:MouseEvent):void
{
if (consumer != null) {
// 取消订阅
consumer.unsubscribe();
consumer.removeEventListener(MessageEvent.MESSAGE, messageHandler);
consumer = null;
timeText.text = "systime";
}
}
private function messageHandler(event:MessageEvent):void
{
var time:String = event.message.body as String;
timeText.text = time;
}消息订阅也可以采用MultiTopicProducer，能够在单个消息处理程序中同时订阅主题，通过addSubscription(topic)方法订阅主题，removeSubscription(topic)取消订阅。Consumer只能订阅单个主题。
所有代码已写完，启动项目进行测试！1.订阅消息：打开链接http://localhost:8080/FlexDemo/FlexDemo.html，点击显示时间订阅time消息，点击隐藏时间取消订阅
2.推送消息：打开链接http://localhost:8080/FlexDemo/mvc/push?cmd=start推送消息，http://localhost:8080/FlexDemo/mvc/push?cmd=stop停止推送
经过测试，my-streaming-amf、my-polling-amf两个通道都可以实现消息推送订阅，但my-streaming-amf发送订阅请求后会一直维护这一个请求直到取消订阅，my-polling-amf会根据配置文件中设定的时间间隔，每过一段时间发送一次订阅请求，获得后台订阅的信息。
最后附完整代码下载地址：http://download.csdn.net/detail/sjepy/5522399