CODEWITHSUNDEEP
jspspring-mvcspring-security
Supra
Supra

Reputation: 1652

How to display image in jsp in a spring application

I have certain images that are uploaded by users of my application, and should only be accessed by them. How can I display them as thumbnails or otherwise. I store the images in filesystem (outside webapp), and only store their path in the db.

One option that I found was to configure tomcat to expose that directory via following changes in server.xml.

<Context path="/images" docBase="/home/app/basedir" />

And then access images via 

localhost:8080/context/images/b1sd2e09102.jpg

etc. (I am using UUID to generate random image names so that they can not be guessed)

However, this is not an ideal solution for me as the url (if known by other users somehow) is still public. Currently I am able to download them via following in my spring controller: 

@RequestMapping(value = "/download", method = RequestMethod.GET)
public void download(Model model, @RequestParam("id") String key, HttpServletResponse response) throws Exception {
    //get item from db first based on key
    Item item = dbservice.get(key);
    InputStream is = new FileInputStream(item.getPath());     
    response.setHeader("Content-Disposition", "attachment; filename=" + item.getFileName());
    IOUtils.copy(is, response.getOutputStream());
    response.flushBuffer();
    ....
}

Is there a way to render these images on the browser ?

Upvotes: 0

Views: 633

Answers (1)

Serge Ballesta
Serge Ballesta

Reputation: 149165

You were not far from a complete solution. I currently use something near from your example. I simply add a Content-Length header and use an Image/xxx content type that I store in database when the file is uploaded. If it is not present, I use the extension of the original name.

So it could look like :

@RequestMapping(value = "/download", method = RequestMethod.GET)
public void download(Model model, @RequestParam("id") String key, HttpServletResponse response) throws Exception {
    //get item from db first based on key
    Item item = dbservice.get(key);
    InputStream is = new FileInputStream(item.getPath());
    String type = item.getFileType();
    if ((type == null) || (type.isEmpty())) {
        String name = item.getFileName();
        if (name.length > 2) {
            int i = name.substring(0, name.length() - 1).lastIndexOf(".");
            if (i > 0) {
                type = "Image/" + name.substr(i + 1);
            }
        }
    }
    if ((type == null) || (type.isEmpty())) {
        tyoe = "application/octet-stream";
    }
    response.setHeader("Content-Type", type);
    int l = item.getFileLength();
    if (l > 0) {
        response.setContentLength((int) resource.contentLength());
    }
    response.setStatus(HttpServletResponse.SC_OK);
    IOUtils.copy(is, response.getOutputStream());
    response.flushBuffer();
    ....
}

Now, you only have to put an image tag where you want the browser to insert the image

<img src="/appContext/dowload?id=key"/>

But you should alse put the size and eventually the type in the image tag.

Upvotes: 1

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