IllegalStateException after canceling file downloading.

[pawan chopra]

Hi All,

I am providing a file download option to the user in my web-application. Suppose user selects cancel the downloads, I am getting IllegalStateException. I am using tomcat and spring MVC. Kindly let me know how to handle this exception.

here is my code which downloads the file:

 public void downloadFile(HttpServletRequest req,
			HttpServletResponse resp, String pathOfFile) throws IOException {
		File file = null;
		// Decode the file name (might contain spaces and on) and prepare file
		// object.

		if (pathOfFile.contains("cache"))
			file = new File(bimSettings.getReportCacheDir()
					+ pathOfFile.substring(pathOfFile.indexOf("=") + 1));
		else if(pathOfFile.contains("csv"))
			file = new File("c:/reportCSV/csv.zip");
		else
			file = new File(bimSettings.getCurrentPath() + "/WEB-INF/"
					+ pathOfFile);
		// Check if file actually exists in filesystem.
		if (!file.exists()) {
			// Do your thing if the file appears to be non-existing.
			// Throw an exception, or show default/warning page, or just ignore
			// it.
			System.out.println("here is the error!!");
			errors.addError("error.no.file");
			return;
		}
		String contentType = null;
		// Get content type by filename.
		if (pathOfFile.contains("cache"))
			contentType = getServletContext().getMimeType(
					pathOfFile.substring(pathOfFile.lastIndexOf("/")));
		else
			contentType = getServletContext().getMimeType(pathOfFile);
		// If content type is unknown, then set the default value.
		// For all content types, see:
		// http://www.w3schools.com/media/media_mimeref.asp
		// To add new content types, add new mime-mapping entry in web.xml.
		if (contentType == null) {
			contentType = "application/octet-stream";
		}

		// Prepare streams.
		BufferedInputStream input = null;
		BufferedOutputStream output = null;

		try {
			// Open file.
			input = new BufferedInputStream(new FileInputStream(file),
					DEFAULT_BUFFER_SIZE);

			// Init servlet response.
			resp.reset();
			resp.setContentType(contentType);
			resp.setContentLength(input.available());
			resp.setHeader("Content-disposition", "attachment; filename=\""
					+ file.getName() + "\"");
			output = new BufferedOutputStream(resp.getOutputStream(),
					DEFAULT_BUFFER_SIZE);

			// Write file contents to response.
			byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
			for (int length; (length = input.read(buffer)) != -1;) {
				output.write(buffer, 0, length);
			}

			// Finalize task.
			output.flush();
		} catch (IllegalStateException e) {
			// Do your thing with the exception. Print it, log it or mail
			// it.
			logger.error("User canceled the download"+e.getMessage());
		}finally {
			// Gently close streams.
			close(output);
			close(input);
		}
	}


	/**
	 * close all the resources
	 * @param resource
	 */
	private static void close(Closeable resource) {
		if (resource != null) {
			try {
				resource.close();
			} catch (IOException e) {
				// Do your thing with the exception. Print it, log it or mail
				// it.
				logger.error("IO Exception occured"+e.getMessage());
			} catch (IllegalStateException e) {
				// Do your thing with the exception. Print it, log it or mail
				// it.
				logger.error("User canceled the download"+e.getMessage());
			}
		}
	}   

[David O'Meara]

It looks like you handled it. If you wanted to do something else, you could also do it in the 'catch' block.

[pawan chopra]

I don't want that the exception thrown should display on the tomcat console. But it is showing.

[Vijitha Kumara]

I don't want that the exception thrown should display on the tomcat console. But it is showing.

That's because your logger may have configured to do so.

[Mohamed Inayath]

The IllegalStateException could be because you are trying to close (close(output); ) the resource(resource.close();).

I believe the response is committed and you are trying to close.

[David O'Meara]

I agree with Vijitha Kumara: if you don't want it logged, then don't log it.

[pawan chopra]

Thanks to all of you, my mistake I was trying to open the response output stream again in some other method