今晚，原本想來寫一個 Flash 8 的上傳程式，由 Java 接收檔案並儲存起來。結果在練習這個範例的過程中，遇到些問題尚未找出答案。

Java 的程式碼如下：

package idv.ben.file;

import java.io.*;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.*;

public class Upload extends javax.servlet.http.HttpServlet
	implements javax.servlet.Servlet {
	static final private long serialVersionUID = 1L;	 
	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			System.out.println("==標頭==");
			Enumeration enum = request.getHeaderNames();
			while(enum.hasMoreElements()){
				String header = (String)enum.nextElement();
				System.out.println(header + " = " + request.getHeader(header));
			}
			
			// Create a new file upload handler
			DiskFileUpload upload = new DiskFileUpload();
			
			// Parse the request
			List items = upload.parseRequest(request);
			
			// Process the uploaded items
			Iterator iter = items.iterator();
			while (iter.hasNext()) {
			    FileItem item = (FileItem) iter.next();

		    	String fieldName = item.getFieldName();
		        String fileName = item.getName();
		        String contentType = item.getContentType();
		        boolean isInMemory = item.isInMemory();
		        long sizeInBytes = item.getSize();

		        System.out.println("==檔案==");
		        System.out.println("fieldName = " + fieldName);
		        System.out.println("fileName = " + fileName);
		        System.out.println("contentType = " + contentType);
		        System.out.println("isInMemory = " + isInMemory);
		        System.out.println("sizeInBytes = " + sizeInBytes);
			        
		        String fileNameMain = fileName.lastIndexOf("")==-1?fileName:fileName.substring(fileName.lastIndexOf("")+1);
		        System.out.println("fileNameMain = " + fileNameMain);
				        
		        File uploadDir = new File(this.getServletContext().getRealPath("/files"));
		        if(!uploadDir.exists())uploadDir.mkdir();
		        
		        File uploadedFile = new File(this.getServletContext().getRealPath("/files/" + fileNameMain));
		        item.write(uploadedFile);
			}
		} catch (FileUploadException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}   	  	    
}

我是利用 http://jakarta.apache.org/commons/fileupload/ 提供的 FileUpload 來作操作的，當收到上傳的檔案後，會將之儲存在名叫 files 的資料夾中。

以下是 Flash 8 的程式碼：

import flash.net.FileReference;
var allTypes:Array = new Array();
var imageTypes:Object = new Object();
imageTypes.description = "Images (*.jpg, *.jpeg, *.gif, *.png)";
imageTypes.extension = "*.jpg; *.jpeg; *.gif; *.png";
allTypes.push(imageTypes);
var listener:Object = new Object();
listener.onSelect = function(file:FileReference):Void  {
	trace("onSelect: "+file.name);
	if (!file.upload("http://localhost/Flash_Upload/Upload")) {
		trace("Upload dialog failed to open.");
	}
};
listener.onCancel = function(file:FileReference):Void  {
	trace("onCancel");
};
listener.onOpen = function(file:FileReference):Void  {
	trace("onOpen: "+file.name);
};
listener.onProgress = function(file:FileReference, bytesLoaded:Number, bytesTotal:Number):Void  {
	trace("onProgress with bytesLoaded: "+bytesLoaded+" bytesTotal: "+bytesTotal);
};
listener.onComplete = function(file:FileReference):Void  {
	trace("onComplete: "+file.name);
};
listener.onHTTPError = function(file:FileReference):Void  {
	trace("onHTTPError: "+file.name);
};
listener.onIOError = function(file:FileReference):Void  {
	trace("onIOError: "+file.name);
};
listener.onSecurityError = function(file:FileReference, errorString:String):Void  {
	trace("onSecurityError: "+file.name+" errorString: "+errorString);
};
var fileRef:FileReference = new FileReference();
fileRef.addListener(listener);
fileRef.browse(allTypes);

其實在這其中，大部分都還是從 help 的範例程式碼中擷取出來使用的，當 Flash 一開始執行時，在 frame 1 就叫用 FileReference 的 browse() 來取得使用者電腦中的檔案，若是觸發 select 事件的話，就執行 upload() 上傳。

執行之後，Flash 中 trace() 出來的訊息如下：

onSelect: IMG_2940.JPG
onOpen: IMG_2940.JPG
onProgress with bytesLoaded: 32768 bytesTotal: 865102
onProgress with bytesLoaded: 65536 bytesTotal: 865102
onProgress with bytesLoaded: 131072 bytesTotal: 865102
onProgress with bytesLoaded: 196608 bytesTotal: 865102
onProgress with bytesLoaded: 229376 bytesTotal: 865102
onProgress with bytesLoaded: 262144 bytesTotal: 865102
onProgress with bytesLoaded: 294912 bytesTotal: 865102
onProgress with bytesLoaded: 327680 bytesTotal: 865102
onProgress with bytesLoaded: 458752 bytesTotal: 865102
onProgress with bytesLoaded: 589824 bytesTotal: 865102
onProgress with bytesLoaded: 655360 bytesTotal: 865102
onProgress with bytesLoaded: 688128 bytesTotal: 865102
onProgress with bytesLoaded: 720896 bytesTotal: 865102
onProgress with bytesLoaded: 786432 bytesTotal: 865102
onProgress with bytesLoaded: 851968 bytesTotal: 865102
onProgress with bytesLoaded: 865102 bytesTotal: 865102
onComplete: IMG_2940.JPG

Java 這邊背後輸出的訊息卻是：

==標頭==
accept = text/*
content-type = multipart/form-data; boundary=----------gL6cH2ae0ei4KM7Ef1gL6Ef1gL6GI3
user-agent = Shockwave Flash
host = localhost
content-length = 0
connection = Keep-Alive
cache-control = no-cache
==標頭==
accept = text/*
content-type = multipart/form-data; boundary=----------gL6cH2ae0ei4KM7Ef1gL6Ef1gL6GI3
user-agent = Shockwave Flash
host = localhost
content-length = 865520
connection = Keep-Alive
cache-control = no-cache
org.apache.commons.fileupload.FileUploadException: Processing of multipart/form-data request failed. Stream ended unexpectedly
	at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:429)
	at idv.ben.file.Upload.doPost(Upload.java:27)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
	at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
	at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
	at java.lang.Thread.run(Thread.java:595)

為了單純測試這個上傳 Java 是否有問題，所以我另外做了一個 test.html 來讓事情單純一點，果然就可以正常上傳成功了，Java 輸出的訊息為：

==標頭==
accept = */*
referer = http://localhost/Flash_Upload/test.html
accept-language = zh-tw
content-type = multipart/form-data; boundary=---------------------------7d5731c8019a
accept-encoding = gzip, deflate
user-agent = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)
host = localhost
content-length = 865371
connection = Keep-Alive
cache-control = no-cache
==檔案==
fieldName = file
fileName = C:Documents and SettingsBenMy DocumentsMy Pictures20050917_摩奇晚餐photosIMG_2940.JPG
contentType = image/pjpeg
isInMemory = false
sizeInBytes = 865102
fileNameMain = IMG_2940.JPG

由上面的比對當中，由錯誤訊息 org.apache.commons.fileupload.FileUploadException: Processing of multipart/form-data request failed. Stream ended unexpectedly at idv.ben.file.Upload.doPost(Upload.java:27) 來看，我一開始猜測會不會是因為 Flash 對外傳遞資料時的封包結尾字元有什麼特別之處。後來看到 html 與 Flash 的兩個測試比對後，感覺上又沒有什麼關鍵的大不同之處。只是，有點詭異的是，發生錯誤時，header 標頭的部份被印出兩次，而且其中的第一次還有 content-length = 0 這個項目，第二次卻為 content-length = 865520。這些資訊讓我還有點摸不著頭緒。

我用來測試的 Flash 版本，還是先前的測試版軟體，所以我也不敢保證是否是測試版的問題，但是以前也有人可以寫出正常的效果，所以我也在想會不會是我以 Java 實做時，少考慮了什麼部份。原本以為只要 html 版的上傳能正常執行，應該前端就只是由 html 換成 Flash 而已，後端應該不用有任何改變才對，不過，現在看來，一定還有什麼遺漏之處。