flex amf的使用

AMF是Adobe独家开发出来的通信协议，它采用二进制压缩，序列化、反序列化、传输数据，从而为Flash 播放器与Flash Remoting网关通信提供了一种轻量级的、高效能的通信方式。如下图所示：


AMF(Action Message Format)是一种 binary format的资料型态，透过 AMF overHTTP的方式将flash端资料编码后传回server，server端的remotingadaptor接收到资料后则会译码回正确的native对象，交给正确的程序处理。

AMF最大的特色在于可直接将Flash内置对象，例如Object, Array, Date, XML，传回服务器端，并且在服务器端自动进行解析成适当的对象，这就减轻了开发人员繁复工作，同时也更省了开发时间。由于AMF采用二进制编码，这种方式可以高度压缩数据，因此非常适合用来传递大量的资料。数据量越大，Flash Remoting的传输效能就越高，远远超过Web Service。至于XML, LoadVars和loadVariables() ，它们使用纯文本的传输方式，效能就更不能与Flash Remoting相提并论了。

注意：Flash Remoting需要浏览器支持Binary POST，Flash 播放器在Netscape 6.x.环境下运行Flash Remoting会不起作用（Flash Remoting调用没有效果也不返回错误）， Netscape 7已经纠正了这个bug 。对于早期Safari和Chimera版的苹果机也有这个问题。


下面是一个flex amf socket连接例子：

java服务器代码：

/*  
 * To change this template, choose Tools | Templates  
 * and open the template in the editor.  
 */  
package sockeserver;   
  
import java.io.*;   
import java.net.ServerSocket;   
import java.net.Socket;   
  
  
import flex.messaging.io.*;   
import flex.messaging.io.amf.*;   
import java.util.HashMap;   
import java.util.Map;   
import java.util.zip.DeflaterOutputStream;   
  
/**  
 *  
 * @author  mumuyu99  
 */  
public class socketServer implements Runnable {   
  
    public static void main(String[] args) {   
start();   
  
    }    //****************************************************************//   
    private static boolean isRunning = false;           //服务器运行标志   
    ServerSocket ss = null;                         //socket连接   
    int userIndexNumber;                            //用户索引号   
    int userCount;                                  //房间人数   
    //Iterator it=null;                             //迭代器   
    //*************************消息协议*********************************//   
    private byte type;                                          //消息类型   
    private byte mainCmd;                                       //消息主命令   
    private byte subCmd;                                        //消息子命令   
    private byte[] data;                                        //消息数据   
    private SerializationContext context = new SerializationContext();   
  
    public static void start() {   
        socketServer server = new socketServer();   
  
        // server.heardHeart();   
        new Thread(server).start();   
        System.out.println("服务器打开");   
    }   
  
    public void run() {   
        try {   
            isRunning = true;   
            try {   
                ss = new ServerSocket(9999);   
            } catch (IOException ex) {   
                System.out.println(ex.toString());   
            }   
            Socket socket;   
            while (isRunning) {   
                socket = ss.accept();   
                handleCmd(socket);   
            }   
  
        } catch (IOException ex) {   
            System.out.println(ex.toString());   
        }   
  
  
    }   
  
    private void handleCmd(Socket inComing) {   
        try {   
            DataInputStream dis = new DataInputStream(inComing.getInputStream());   
            DataOutputStream dos = new DataOutputStream(inComing.getOutputStream());   
  
  
  
  
            System.out.println("准备好接收数据！");   
  
            byte[] lang = new byte[dis.available()];   
            dis.read(lang);   
            System.out.println(new String(lang, "utf-8"));   
  
            Amf3Output out = new Amf3Output(context);   
            DeflaterOutputStream stream = new DeflaterOutputStream(dos);   
            out.setOutputStream(stream);   
  
            Map map = new HashMap();   
            String[] arr = "1,2,3,4,5".split(",");   
  
            map.put("datas", arr);   
            map.put("userName", "mumuyu99");   
            map.put("fullName", "最新消息");   
             
  
            out.writeObject(map);   
            stream.finish();   
  
            dos.writeUTF("你好啊");   
  
            dos.flush();   
  
  
  
        } catch (IOException ex) {   
            System.out.println(ex.toString());   
        }   
  
  
    }   
}  

Flex端的代码如下：

<?xml version="1.0" encoding="utf-8"?>   
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/halo" minWidth="1024" minHeight="768"  
       
       
    >   
       
    <fx:Script>   
    <!--[CDATA[   
           
        import flash.net.Socket;   
        import mx.controls.Alert;   
           
           
           
        private static var socket:Socket;   
           
        private var byteaa:ByteArray;   
        private function connectSocket():void{   
               
               
            socket=new Socket("localhost",9999)   
            //socket.objectEncoding=ObjectEncoding.AMF3;
                   
            var byteArray:ByteArray=new ByteArray();   
               
            var s:String="hello word!"  
                   
                   
                   
            byteArray.writeUTFBytes(s);   
            socket.writeBytes(byteArray,0,byteArray.length);   
            socket.writeMultiByte(s,"UTF-8");   
            socket.flush();   
            byteaa=new ByteArray();   
            socket.addEventListener(ProgressEvent.SOCKET_DATA,loaderHandler);   
            socket.addEventListener(IOErrorEvent.IO_ERROR,errorIO);   
            socket.addEventListener(Event.CONNECT,connectStart);   
               
               
        }   
           
        private function connectStart(event:Event):void{   
            Alert.show("连接成功！");   
        }   
        private function errorIO(event:IOErrorEvent):void{   
            Alert.show("连接不到数据源！");   
        }   
           
        private function loaderHandler(event:ProgressEvent):void {     
  
            //  var intervalId:uint = setTimeout(laoderInit,100);   
            laoderInit();   
        }     
           
           
        private function laoderInit():void{   
               
               
            var start:Number=getTimer();     
               
               
               
            while(socket.bytesAvailable>0){   
                   
                socket.readBytes(byteaa);      
                   
            }   
               
            byteaa.uncompress();   
               
               
               
               
            var obj:Object = byteaa.readObject();   
            Alert.show(obj.fullName);   
               
            var end:Number=getTimer();      
            Alert.show("耗时：" + (end - start) + "毫秒");    
               
        }   
           
           
        protected function button1_clickHandler(event:MouseEvent):void  
        {   
            connectSocket();   
               
        }   
    ]]-->   
    </fx:Script>   
       
    <s:Button x="190" y="370" label="连接" enabled="true"  click="button1_clickHandler(event)"/>   
       
</s:Application>