How to get the contentType of some files?

Question

Hi all,
I'd like to provide the end-user the ability to download files from the server.
for this, I have to provide the content type in:
(HttpServletResponse)
response.setContentType( ????? );  I wrote the method below, but I realized that I'm still missing files such as CSV or outlook emails.
Q: is there any generic content type so it will download all files? or do I have to keep this method updated?
thanks for any pointers
     public static String getContentType(String extension)
          if (extension.equalsIgnoreCase("doc"))          
               return "application/msword";
          if (extension.equalsIgnoreCase("xls"))          
               return "application/vnd.ms-excel";
          if (extension.equalsIgnoreCase("pdf"))          
               return "application/pdf";
          if (extension.equalsIgnoreCase("ppt"))          
               return "application/ppt";
          if (extension.equalsIgnoreCase("jpg"))          
               return "image/jpeg";
          if (extension.equalsIgnoreCase("gif"))          
               return "image/gif";
          if (extension.equalsIgnoreCase("html"))          
               return "text/html";
          if (extension.equalsIgnoreCase("htm"))          
               return "text/html";
          if (extension.equalsIgnoreCase("rtf"))          
               return "application/rtf";
          if (extension.equalsIgnoreCase("zip"))          
               return "application/zip";
          if (extension.equalsIgnoreCase("txt"))          
               return "text/plain";
          if (extension.equalsIgnoreCase("bmp"))          
               return "image/x-bitmap";
          return "application/octet-stream";
     }

Answer 1

URLConnection#guessContentTypeFromName() might be sufficient.
Also see the downloadFile() snippet at the bottom of this article: http://balusc.xs4all.nl/srv/dev-jep-pdf.html