Simplest way to serve static data from outside the application server in a Java web application

user_90563 0
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I have a Java web application running on Tomcat. I want to load static images that will be shown both on the Web UI and in PDF files generated by the application. Also new images will be added and saved by uploading via the Web UI.

It's not a problem to do this by having the static data stored within the web container but storing and loading them from outside the web container is giving me headache.

I'd prefer not to use a separate web server like Apache for serving the static data at this point. I also don't like the idea of storing the images in binary in a database.

I've seen some suggestions like having the image directory being a symbolic link pointing to a directory outside the web container, but will this approach work both on Windows and *nix environments?

Some suggest writing a filter or a servlet for handling the image serving but those suggestions have been very vague and high-level without pointers to more detailed information on how to accomplish this.

static-content jakarta-ee servlets tomcat
10 Answers
user_724780

if anyone not able to resolve his problem with accepted answer, then note these below considerations:

  1. no need to mention localhost:<port> with <img> src attribute.
  2. make sure you are running this project outside eclipse, because eclipse creates context docBase entry on its own inside its local server.xml file.
user_34227260

Read the InputStream of a file and write it to ServletOutputStream for sending binary data to the client.

  • Local file You can read a file directly using FileInputStream('path/image.png').
  • Mongo DataBase file's you can get InputStream using GridFS.
@WebServlet("/files/URLStream")
public class URLStream extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public URLStream() {
        super();
    }

    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        File source = new File("D:\\SVN_Commit.PNG");
        long start = System.nanoTime();

        InputStream image = new FileInputStream(source);

        /*String fileID = request.getParameter("id");
        System.out.println("Requested File ID : "+fileID);
        // Mongo DB GridFS - https://stackoverflow.com/a/33544285/5081877
        image = outputImageFile.getInputStream();*/

        if( image != null ) {
            BufferedInputStream bin = null;
            BufferedOutputStream bout = null;
            ServletOutputStream sos = response.getOutputStream();
            try {
                bin = new BufferedInputStream( image );
                bout = new BufferedOutputStream( sos );
                int ch =0; ;
                while((ch=bin.read())!=-1) {
                    bout.write(ch);
                }
            } finally {
                bin.close();
                image.close();
                bout.close();
                sos.close();
            }

        } else {
            PrintWriter writer = response.getWriter();
            writer.append("Something went wrong with your request.");
            System.out.println("Image not available.");
        }
        System.out.println("Time taken by Stream Copy = "+(System.nanoTime()-start));
    }
}

Result the URL directly to the src attibute.

<img src='http://172.0.0.1:8080/ServletApp/files/URLStream?id=5a575be200c117cc2500003b' alt="mongodb File"/>
<img src='http://172.0.0.1:8080/ServletApp/files/URLStream' alt="local file"/>

<video controls="controls" src="http://172.0.0.1:8080/ServletApp/files/URLStream"></video>
user_50818770
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