Servlet sends zip file to client

[sindy lee]

Hi, everyone,
I have a problem and need your help. My servlet is:

    private void doPost(String method, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
    {
    	long timestart = -1L;
    	long accumulatedTimeStart = -1;

    	if(_logTime)
    	{
    		accumulatedTimeStart = _accumulatedProcessTime;
    		timestart = System.currentTimeMillis();
    	}

    	_baosLog.reset();

    	String headerFlagString = DataProviderDefinitions.RESPONSE_DATA_HEADER_FLAG_DATAOK;
    	boolean errorTrace = true;
    	String resultString = null;
    	try
    	{
//    		 read the handler parameter submitted to this via the http request call    		
    		String workdir = request.getParameter("zipmaildir");
			String zipfiles = getRequestFilename(request, DataProviderDefinitions.REQUEST_PARAMETER_NAME_FILE);
			if(zipfiles != null && zipfiles.length() != 0){
				_pwLog.println("zipfiles1:   " +  zipfiles);
				if(zipfiles != null && zipfiles.length() != 0){
					StringTokenizer mtzip = new StringTokenizer(zipfiles,",");
					int ntok = mtzip.countTokens();
					String zipfile = "";
					for(int tt = 0; tt < ntok; tt++)
					{
						String token = mtzip.nextToken();
						zipfile = token;
						if(zipfile != null && zipfile.length() != 0){
							File zfile = getSingleFile(zipfile, request);
							if(zfile != null && zfile.exists())
							{
								_pwLog.println("zipfiles2:   " +  zfile);
								_zpfiles.add(zfile);								
							}
						}
					}
					makezipfile(_zpfiles, workdir);
				}
			}		
} catch(Exception e){}           

    	} catch(Exception any)
    	{
    		headerFlagString = DataProviderDefinitions.RESPONSE_DATA_HEADER_FLAG_ERRORS;

    		if(_logErrors)
    		{
    			_pwLog.println("Error in WebserverMakezipfileHandler.doall(..):");
    			_pwLog.println(any.getMessage());
    			_pwLog.println("Error trace:");
    			any.printStackTrace(_pwLog);
    		}

    		// write the response
    		ByteArrayOutputStream baosResponse = new ByteArrayOutputStream(40960);
    		PrintWriter psResponse = new PrintWriter(
    				new BufferedWriter(new OutputStreamWriter(baosResponse, DataProviderDefinitions.TEXT_CONTENT_ENCODING_FOR_TRANSFER)), true);

    		// write the error to the response
    		if(errorTrace)
    		{
    			psResponse.println("Error in WebserverMakezipfileHandler.doall(..):");
    			psResponse.println(any.getMessage());
    			psResponse.println("Error trace:");
    			any.printStackTrace(psResponse);
    		}
    		else
    		{
    			psResponse.println(any.getMessage());
    		}

    		psResponse.flush();

    		// send the error response

    		response.setContentType(DataProviderDefinitions.CONTENT_TYPE_BINARY_DATA);
    		ServletOutputStream sos = response.getOutputStream();
    		DataOutputStream dos = new DataOutputStream(sos);

    		// write the header flag            
    		dos.writeUTF(headerFlagString);            
    		// write the error data

    		byte[] bytes = baosResponse.toByteArray();
    		dos.write(bytes, 0, bytes.length);
    		dos.flush();
    		dos.close();
    	}

    	_pwLog.flush();

    	if(_baosLog.size() > 0)
    	{
    		if(_logTime)
    		{
    			long timeend = System.currentTimeMillis();
    			_accumulatedProcessTime = _accumulatedProcessTime + timeend - timestart;
    			_pwLog.println("accumulated process time at start [ms]: "+accumulatedTimeStart);
    			_pwLog.println("accumulated process time at end   [ms]: "+_accumulatedProcessTime);
    			_pwLog.flush();
    		}

    		WebserverServletLog.writeLogBytes(this, method, _baosLog.toByteArray());
    	}

    	_baosLog.reset();
    }	    


public void makezipfile(Vector urlsnew, String workdir){

	// Create a buffer for reading the files					    
	byte[] buf = new byte[4096];	                	
	try {
		Vector nofile = new Vector();
//    	String zippath = workdir;
//		FileOutputStream fos = new FileOutputStream(zippath);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		filezip = new ZipOutputStream(baos);
		// Compress the files
		for (int ii=0; ii<urlsnew.size(); ii++) {
			File cwf = (File)urlsnew.get(ii);
			if(!cwf.isDirectory()){
				String thePath = cwf.getPath();
//				File tmpf = new File(thePath);
				if(cwf.exists()){
					_pwLog.println("zipfiles" + ii + "  is: " + thePath + "  " + cwf.getPath());
					FileInputStream in = new FileInputStream(thePath);
					filezip.putNextEntry(new ZipEntry(thePath));
					int len;
					while ((len = in.read(buf)) > 0) {
						filezip.write(buf, 0, len);
					}
					filezip.closeEntry();
					in.close();
				}
				else   nofile.add(cwf.getName());
			}
		}
		// Complete the ZIP file
		filezip.close();	
		baos.close();
//		fos.flush();
//		fos.close();
	} catch (IOException e1) {
		e1.printStackTrace();
	}
}

And my client is:

	public void makezipfilebyservlet(Vector urlsnew) throws Exception{

		DataProvider dp = DataProvider.getInstance();	
		String query = "";
		CWFile out_file_dest = null;
		StringBuffer sb = new StringBuffer(urlsnew.size());
		StringBuffer sb2 = new StringBuffer(urlsnew.size());
		String cont1 = "";
		String cont2 = "";
		if(urlsnew != null && urlsnew.size() != 0){
			for(int u=0; u<urlsnew.size(); u++){
				out_file_dest = (CWFile)urlsnew.get(u);
				String indent = ",";
				cont1 = out_file_dest.getEncodedUrlString();
				cont1 = cont1 + indent;
				sb.append(cont1);
			}
		}   		
		String zippath = "zipmaildir.zip";
		query = DataProviderDefinitions.REQUEST_PARAMETER_NAME_FILE + "=" + sb.toString()
		+ "&" +
		"zipmaildir" + "=" + zippath;
		String servletUri = dp.getEncodedWebApplicationBasisURL() + DataProviderDefinitions.SERVLET_MAKE_ZIPFILE_HANDLER;

		if(DataProvider.BE_VERBOSE)
		{
			System.out.println("MailDialog.makezipfilebyservlett():");
			System.out.println("    servletUri: "+servletUri);
			System.out.println("  makezipfilebyservlet  query     : "+query);
		}
		System.out.println("MailDialog.makezipfilebyservlet():");
		System.out.println("    servletUri: "+servletUri);
		System.out.println("  makezipfilebyservlet  query     : "+query);

		// make the connection

		URL servletURL = new URL(servletUri);
		URLConnection urlConnection = servletURL.openConnection();
		_connection = (HttpURLConnection)urlConnection;		
		_connection.setRequestMethod("POST");
		_connection.setDoInput(true);
		_connection.setDoOutput(true);
		_connection.setRequestProperty("accept", DataProviderDefinitions.CONTENT_TYPE_BINARY_DATA + ", " + DataProviderDefinitions.CONTENT_TYPE_PLAIN_TEXT);
		_connection.setReadTimeout(0);

		try
		{
			DataProviderClientUtils.connectToWebserver(_connection);
		} catch(Exception any)
		{
			dp._webserverIsUp = false;
			System.out.println("MailDialog.sendmail(): connectToWebserver Exception");
		}

		// send the query string
		urlConnection = servletURL.openConnection();
		_connection = (HttpURLConnection)urlConnection;	
		_connection.setRequestMethod("POST");
		_connection.setDoInput(true);
		_connection.setDoOutput(true);
		_connection.setRequestProperty("accept", DataProviderDefinitions.CONTENT_TYPE_BINARY_DATA + ", " + DataProviderDefinitions.CONTENT_TYPE_PLAIN_TEXT);
		_connection.setReadTimeout(0);
		_os = _connection.getOutputStream();
		System.out.println("MailDialog.sendmail() _os: " + _os);		
		if(_os == null)
		{
			System.out.println("MailDialog.sendmail(): OutputStream is null.");
			throw new Exception("MailDialog.sendmail(): OutputStream is null.");
		}
		else
		{
			_pw = new PrintWriter(_os);
			_pw.print(query);
			_pw.flush();
			DataOutputStream dos = new DataOutputStream(_os);          

			try
			{
				dos.flush();
			} catch(Exception any){}
			try			{
				dos.close();
			} catch(Exception any){}
			try
			{
				_os.close();
			} catch(Exception any){}
//			 receive the data   
		}
  // add to attachment
		InputStream is = _connection.getInputStream();
		if(is != null){
			DataInputStream dis = new DataInputStream(is);
			//		String headerFlag = dis.readUTF();
			int buffsize = 4096;
			ByteArrayOutputStream baos = new ByteArrayOutputStream(buffsize);
			byte[] bytes = new byte[buffsize];
			int len = 0;
			while((len = dis.read(bytes, 0, buffsize)) >= 0)
			{
				baos.write(bytes, 0, len);
				baos.flush();
			}
			dis.close();
//			bytes = baos.toByteArray();
//			baos.close();			
			FileOutputStream fos = new FileOutputStream(zippath);
			baos.writeTo(fos);
			baos.close();
//			fos.write(bytes);		
			fos.close();
		}		
//		String zipfiles = GetResponseString();
//		System.out.println("MailDialog.makezipfile() ok: " + zipfiles); 
		// add to attachment
		File zip = new File("zipmaildir.zip");
		_attachedFiles.add(zip);  // I want to get the zip files from servlet response and put them into a Vector "_attachedFile" 
	}

The Problem is, if i try to open my "zipmaildir.zip", it tells me "the file can not opened, it is not a zip file". So what's wrong here? How should i send my compressed files stream to client, and how can i convert it to a file?