flex 与 后台通讯

public function submit():void{
    
    //要请求的URL
    var request:URLRequest = new URLRequest("http://localhost:8086/test.do") ;
    var load:URLLoader = new URLLoader() ;
    //URL参数
    var variables:URLVariables = new URLVariables();
    
    //variables.+后面的参数 表示要提交的参数。
    variables.content = content.text;
    
    variables.no = 1001 ;
    //提交的方式
    request.method=URLRequestMethod.POST;
    
    //提交的数据
    request.data=variables ;
    
    load.dataFormat = URLLoaderDataFormat.TEXT ;
    load.load(request) ;
    
   }
后台通过：
String content = request.getParameter("content") 获取；
String no = request.getParameter("no ") 获取；

var request:URLRequest = new URLRequest(url);  

var urlVar:URLVariables = new URLVariables();  

urlVar.param = valStr;  

request.data = urlVar;  

request.method = URLRequestMethod.POST; 

通过Flex写上传 
我用FlieReference上传 URLRequest作为通信 

查过URLRequest 的api，通常情况下 
通过它的data属性来进行传值  可以使用ByteArray类型 URLVariables 再或者直接字符串 

API中写道 
ByteArray类型不支持POST 以及 FileReference.upload() ， FileReference.download() 

我在网上找过例子使用URLVariables，代码如下 

var request:URLRequest = new URLRequest(url);
var urlVar:URLVariables = new URLVariables();
 urlVar.param = valStr;
 request.data = urlVar;
 request.method = URLRequestMethod.POST;

其中param作为属性名或者说是一个key 而valStr作为value 

而后台使用  (String)request.getParameter("param");来接受 
但挑了很长时间，不管用 后来也不知道是为什么 

看了看API 标明如下 
如果该对象是 URLVariables 对象，并且该方法是 POST，则使用 x-www-form-urlencoded 格式对变量进行编码，并且生成的字符串会用作 POST 数据。一种例外情况是对 FileReference.upload() 的调用，在该调用中变量将作为 multipart/form-data 发布中的单独字段进行发送。 

DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(4096);
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setSizeMax(maxPostSize);
try {
    List fileItems = upload.parseRequest(request);
    Iterator iter = fileItems.iterator();
    while (iter.hasNext()) {
        FileItem item = (FileItem) iter.next();
        if(item.getFieldName().equals("param")) {
                item.getString();
                ........

正常的循环会循环出很多参数，所以需要判断 

这样就可以获取到参数值了　　

Flex中Image控件相关之Java+Flex项目中ByteArray传到服务器端（java端）持久化（文件上传）<?xml version="1.0" encoding="utf-8"?>

Flex 代码：

<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/mx"
               minWidth="955" minHeight="600"
               creationComplete="createHandler()"
               >
    
    <fx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.utils.Base64Encoder;
            
            private function createHandler():void{
                fileRefer.addEventListener(Event.SELECT,selectHandler);    //选择文件
                fileRefer.addEventListener(Event.COMPLETE,completeHandler);//加载完成
            }
            
            
            private function selectHandler(event:Event):void{
                if(fileRefer){
                    fileRefer.load();
                }
            }
            
            private function completeHandler(event:Event):void{
                if(fileRefer){
                    mySource.source = fileRefer.data;
                }
            }
            
            
            private var fileRefer:FileReference = new FileReference();
            protected function sourceFile_clickHandler(event:MouseEvent):void
            {
                // TODO Auto-generated method stub
                fileRefer.browse([new FileFilter("Images(*.jpg;*.gif;*.png)","*.jpg;*.gif;*.png")]);
            }
            
            protected function btn_canvertToImage_clickHandler(event:MouseEvent):void
            {
                // TODO Auto-generated method stub
                if(fileRefer.data){
                    destSource.source = fileRefer.data;
                }
            }
            
            
            private var urlRequest:URLRequest = new URLRequest("http://localhost:9080/ByteArrayApp/persistence");
            protected function btn_persistence_clickHandler(event:MouseEvent):void
            {
                // TODO Auto-generated method stub
                urlRequest.data = fileRefer.data;
                urlRequest.contentType = "application/octet-stream";
                urlRequest.method = URLRequestMethod.POST;
                
                var urlloader:URLLoader = new URLLoader();
                urlloader.dataFormat = URLLoaderDataFormat.BINARY;
                urlloader.addEventListener(Event.COMPLETE,completePersistenceHandler);
                urlloader.load(urlRequest);
            }
            
            private function completePersistenceHandler(event:Event):void{
                Alert.show("持久化成功","恭喜");
            }
        ]]>
    </fx:Script>
    
    <fx:Declarations>
    </fx:Declarations>
    <s:BorderContainer id="sourceFileContainer" x="8" y="30" borderColor="#1F7888" click="sourceFile_clickHandler(event)">
        <s:Image id="mySource" x="0" y="-4" width="130" height="127"/>
    </s:BorderContainer>
    <s:Button id="btn_canvertToImage" x="158" y="93" width="52" height="18" label="==&gt;" chromeColor="#1F7888"
              color="#FEFDFD" click="btn_canvertToImage_clickHandler(event)"/>
    
    <s:BorderContainer id="destSourceContainer" x="224" y="35" borderColor="#1F7888">
        <s:Image id="destSource"  width="130" height="127"/>
    </s:BorderContainer>
    <s:Button id="btn_persistence" x="372" y="90" label="==&gt;持久化到硬盘" chromeColor="#1F7888" click="btn_persistence_clickHandler(event)"/>
    <s:Label x="34" y="167" width="75" height="17" text="点击选择图片"/>
    
</s:Application>

Java服务器端代码：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class PersistenceServlet
 */
@WebServlet("/persistence")
public class PersistenceServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public PersistenceServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        System.out.println("============BEGIN===================");
        
        ServletInputStream servletInputStream = request.getInputStream();
        
        int len = request.getContentLength();
        
        byte buffer[] = new byte[len];
        
        int readlen=0;
        
        FileOutputStream fos = new FileOutputStream(new File("c:/jun.jpg"));
        while((readlen=servletInputStream.read(buffer))!=-1){
            fos.write(buffer, 0, readlen);
        }
        fos.flush();
        fos.close();
        servletInputStream.close();
        System.out.println("============END===================");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }
}