Java EE (Java Enterprise Edition) General Discussion

Hello Everyone,

I tried two approaches to export CSV data and each one gives a different issue.

Approach 1 - Using a Struts Action class and Servlet*

Here the problem is when i export the file, it gives me an option to save/open the file and after that the mouse cursor will show the waiting icon and i cant do anything on the browser window. the browser completely freeze there and i cant do anything on it unless i refresh the page. Anybody know whats going on here? See the code below:

Struts action class

 
public class ExportUserDetail extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) 
    {
	MyForm aForm = (MyForm) form;
	String exportpath = "servlets/ExportServlet?userType="
			+ aForm.getUserType() + "&fromDate=" + aForm.getFromDate()
			+ "&toDate=" + aForm.getToDate() + "&userId="
			+ aForm.getUserId();
	try {
		URI uri = null;
		PageURL urlRender = PageURL.createPageURL(request, response);
		urlRender.setContextualPath(exportpath);
		String urlpath = urlRender.toString();
		urlpath = urlpath.substring(0, urlpath.lastIndexOf("?"));
		uri = new URI(urlpath);
		System.out.println("uri : " + uri);
		response.sendRedirect(uri.toString());

	} catch (Exception e) {
               e.printStackTrace();
	}
	return null;
     }
}

Export Servlet

public class ExportServlet extends HttpServlet 
{
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
	{
			
        ServletOutputStream out = null;
	    BufferedInputStream  bis = null;
        BufferedOutputStream bos = null;   
		try 
		{
			MyForm form = new MyForm();						

			String userType = request.getParameter("userType");
			String fromDate = request.getParameter("fromDate");
			String toDate = request.getParameter("toDate");
			String userId = request.getParameter("userId");

			form.setUserType(userType);
			form.setFromDate(fromDate);
			form.setToDate(toDate);
			form.setUserId(userId);

			List list = AppUtil.getUserNameAndCount(form);
			String outputDocument=getCSVString(list);				
				
			try {
				out = response.getOutputStream ();				
			} catch(IOException e) {		        	
				e.printStackTrace()		           
			}

			response.setContentType("application/vnd.ms-excel");                      
			response.setHeader("Content-disposition","attachment; filename=export.csv");
			bis = new BufferedInputStream(new ByteArrayInputStream(outputDocument.getBytes()));

			bos = new BufferedOutputStream(out);

			byte[] buff = new byte[2048];
			int bytesRead;
			while(-1 != (bytesRead = bis.read(buff, 0, buff.length))){

				bos.write(buff, 0, bytesRead);
				bos.flush();             
			} 
			out.flush(); 
	            
		} catch (Exception e) {
			e.printStackTrace();
		}finally{

			if (out != null) {  	            	
			out.close();
			out = null;
			}

			if (bis != null) {
	          	bis.close();
	           	bis =null;
	        }
	        if (bos != null) {
	           	bos.close();
	           	bos=null;
	        }
		}				
	}
}

Struts.xml file entry.

<action path="/filedownload" type="com.myapp.ExportUserDetail" name="myForm" scope="session" validate="false">
</action>


Approach 2 - Using a Struts DownloadAction class*

This approach is giving me new issue. I got the below error when i tried to execute the ReportDownload Action class. code attached

Error:

<Jun 7, 2011 4:55:23 PM CDT> <Warning> <org.apache.struts.action.RequestProcessor> <BEA-000000> <Unhandled Exception thrown: class java.lang.IllegalStateException>

My Class which extends DownloadAction

public class ReportDownload extends DownloadAction  {

 	protected StreamInfo getStreamInfo(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		MyForm aForm = (MyForm) form;
		List list = ActivityUtil.getUserNameAndCount(aForm);
		String outputDocument = getCSVString(list);
		
		response.setContentType("application/vnd.ms-excel");
		response.setHeader("Content-disposition","attachment; filename=export.slk");
		String contentType = "application/vnd.ms-excel";
		byte[] slkBytes = outputDocument.getBytes();		
		return new ByteArrayStreamInfo(contentType, slkBytes);

	 }
	
	protected class ByteArrayStreamInfo implements StreamInfo 
	{
		protected String contentType;
		protected byte[] bytes;
		public ByteArrayStreamInfo(String contentType, byte[] bytes) {
			this.contentType = contentType;
			this.bytes = bytes;
		}
		public String getContentType() {
			return contentType;
		}
		public InputStream getInputStream() throws IOException {
			System.out.println("getStreamInfo-getInputStream-1" + bytes);
			return new ByteArrayInputStream(bytes);
		}
	}

	public String getCSVString(List list){
		//GENERATES CSV STRING
        return csv.toString();
	}
}

Finally when i ran the application, console printed the SOP line inside the getInputStream function and then i got the "RequestProcessor" error message which is given above.

I am running out of options here. Please help

Edited by: john on Jun 8, 2011 8:13 AM

Edited by: john on Jun 8, 2011 12:19 PM