Convert byte[] to Base64 string for data URI

Question

I know this has probably been asked 10000 times, however, I can\'t seem to find a straight answer to the question.

I have a LOB stored in my db that represents an i

Answer 1

You may also want to consider streaming the images out to the browser rather than encoding them on the page itself.

Here's an example of streaming an image contained in a file out to the browser via a servlet, which could easily be adopted to stream the contents of your BLOB, rather than a file:

  public void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException
  {
    ServletOutputStream sos = resp.getOutputStream();
    try {
      final String someImageName = req.getParameter(someKey);

      // encode the image path and write the resulting path to the response
      File imgFile = new File(someImageName);

      writeResponse(resp, sos, imgFile);
    }
    catch (URISyntaxException e) {
      throw new ServletException(e);
    }
    finally {
      sos.close();
    }
  }

  private void writeResponse(HttpServletResponse resp, OutputStream out, File file)
    throws URISyntaxException, FileNotFoundException, IOException
  {
    // Get the MIME type of the file
    String mimeType = getServletContext().getMimeType(file.getAbsolutePath());
    if (mimeType == null) {
      log.warn("Could not get MIME type of file: " + file.getAbsolutePath());
      resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
      return;
    }

    resp.setContentType(mimeType);
    resp.setContentLength((int)file.length());

    writeToFile(out, file);
  }

  private void writeToFile(OutputStream out, File file)
    throws FileNotFoundException, IOException
  {
    final int BUF_SIZE = 8192;

    // write the contents of the file to the output stream
    FileInputStream in = new FileInputStream(file);
    try {
      byte[] buf = new byte[BUF_SIZE];
      for (int count = 0; (count = in.read(buf)) >= 0;) {
        out.write(buf, 0, count);
      }
    }
    finally {
      in.close();
    }
  }