how to display image which is outside server directory in strtus

Question

This question is continuation to my previous question Accessing External Files Into Our Web Application, actually I am uploading file using struts tag

Answer 1

Hi Below is the answer to my question, I have created ImageServlet for displaying image, steps to perform:

1. you need to add mapping in web.xml file:

    ImageServlet
    /ImageServlet/*

2. create ImageServlet:

public class ImageServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException
    {

        //Setting image path
        ImageLocationService locationService = new ImageLocationService();

        try {
            String imageCategory = request.getParameter("imageCategory");
            if (imageCategory != null) {
                this.imagePath = locationService.getImageLocation(imageCategory);
            }else{
                this.imagePath = ConfigConstants.imageLocation;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        // Get requested image by path info.
        String requestedImage = request.getPathInfo();

        // Check if file name is actually supplied to the request URI.
        if (requestedImage == null) {
            // Do your thing if the image is not supplied to the request URI.
            // Throw an exception, or send 404, or show default/warning image, or just ignore it.
            response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
            return;
        }

        // Decode the file name (might contain spaces and on) and prepare file object.
        File image = new File(imagePath, URLDecoder.decode(requestedImage, "UTF-8"));

        // Check if file actually exists in filesystem.
        if (!image.exists()) {
            // Do your thing if the file appears to be non-existing.
            // Throw an exception, or send 404, or show default/warning image, or just ignore it.
            response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
            return;
        }

        // Get content type by filename.
        String contentType = getServletContext().getMimeType(image.getName());

        // Check if file is actually an image (avoid download of other files by hackers!).
        // For all content types, see: http://www.w3schools.com/media/media_mimeref.asp
        if (contentType == null || !contentType.startsWith("image")) {
            // Do your thing if the file appears not being a real image.
            // Throw an exception, or send 404, or show default/warning image, or just ignore it.
            response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
            return;
        }

        // Init servlet response.
        response.reset();
        response.setBufferSize(DEFAULT_BUFFER_SIZE);
        response.setContentType(contentType);
        response.setHeader("Content-Length", String.valueOf(image.length()));
        response.setHeader("Content-Disposition", "inline; filename=\"" + image.getName() + "\"");

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

        try {
            // Open streams.
            input = new BufferedInputStream(new FileInputStream(image), DEFAULT_BUFFER_SIZE);
            output = new BufferedOutputStream(response.getOutputStream(), DEFAULT_BUFFER_SIZE);

            // Write file contents to response.
            byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
            int length;
            while ((length = input.read(buffer)) > 0) {
                output.write(buffer, 0, length);
            }
        } finally {
            // Gently close streams.
            close(output);
            close(input);
        }
    }

    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.
                e.printStackTrace();
            }
        }
    }
}

3. At jsp side you need to add the mapping in step 1 in your img tag i.e. input type='image':

You can even create Action class and use execute method for doing the same.