Question

I have to show some data and image in the forwarded JSP

To show data I have set the value in the attribute section

request.setAttribute("data", mydata);

I have the image in stream (InputStream) and I can save it as a file too but would like to know if there is a better way of streaming it directly to JSP page.

If I save it using the servlet temp directory “javax.servlet.context.tempdir” then I cannot access it either through

<img src="location of the file set in attribute section"/>

Any preferred way other’s have tried?

Using Tomcat 7.0.33/Java 7

Answer 1

HTTP doesn’t really let you stream images per se, but you could achieve this by piping the data from your InputStream to HttpServletResponse.getOutputStream().

You could have a servlet that is mapped to image files, something like…

<servlet>
    <servlet-name>ImgServlet</servlet-name>
    <servlet-class>ImgServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>ImgServlet</servlet-name>
    <url-pattern>*.jpg</url-pattern>
</servlet-mapping>

And then the servlet class itself can handle the image data stream without having to save it to a file. Something like…

class ImgServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String imageName = request.getRequestURI();
        InputStream data = service.lookUpImage(imageName); //whatever
        IOUtils.copy(data, response.getOutputStream()); // Apache Commons IO
        response.setContentType("image/jpeg");
    }
}

Then the page could just have regular image tags in it.