The correct sequence of operations should be to set the headers first, and then write the contents of the file to the servlet's outputstream. How to develop a Java servlet that allows the user to download a file from the server. open a PDF reader program if the response is a PDF document, etc. In case we want to force the browser always downloads the file, we. Submit comments about this document to: [email protected] Java™ effect until after the container-initiated dispatch has returned to the container.

Servlet Force Pdf

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Hello, In my servlet I am using this code to open a pdf file in a browser, but instead it shows a download dialog box. Any help, what I am doing. Define a Java™ Servlet provided by the framework (typically a controller Java™ Servlet) . Methods added to ServletRequest to force a login and ability to logout . How can i force the browser to ask for the download prompt. May be this is not a ServletOutputStream op = ((HttpServletResponse) context. setHeader(" Content-Disposition", "attachment;");; response.

With no way of telling the original request from the one generated by our redirect, we'll create an infinite loop.

So to differentiate them, we're going to add a temporary token to the URL in the redirect, which we'll verify when it arrives. We don't want an attacker forging this token, so we're going to encrypt the user's source IP address along with a timestamp.

If a request shows up for the PDF file without a valid token, we'll reject it. Or actually, we can force it to be saved to disk, thus preventing the attack from working.

This way, only an attacker from the same IP address who can trick you into clicking a link within 10 seconds of creating it can attack you.

Not perfect, but certainly raises the bar quite a bit. The first step is to add the filter to our application. You can extract the class file from the zip file.

Then we just have to add the following to our web. You should paste this in right above your servlet definitions. You can map multiple url-patterns to the filter if necessary.

Then you could map the filter to apply to ALL requests. If there is demand for this feature, let us know. This code has been only minimally tested.

Spring MVC 4 File Download Example

Please help us verify the approach and the implementation used here. There are not many dependencies here, just the standard Java EE environment. You can compile with:. In the decryptString method, it is necessary to strip the " a" from the end of the str parameter, otherwise an IllegalBlockSizeException will be thrown with "Input length must be multiple of 8 when decrypting with padded cipher".

Jump to: This page contains out-of-date content. The file we are using will be from the webapp resources.

Alternatively, we can do this by describing the mapping in the web. Content-Type is the historical name of the header property.

Force Files to Download (Not Open in Browser)

We now simply refer to the value as the Media Type. For our example, we are using a simple text file.

W3 has a memo on the use of Content-Disposition available to read here. Some browsers will immediately download the file using the given filename and others will show a download dialog containing our predefined value.

The exact action taken will depend on the browser. The size of the byte array we use is arbitrary. We can decide the size based on the amount of memory is reasonable to allocate for passing the data from the InputStream to the OutputStream; the smaller the nuber, the more loops; the bigger the number, the higher memory usage.

This cycle continues until numByteRead is 0 as that indicates the end of the file.Lindy Dobbins. Test again and voila work in Chrome, Firefox and IE. Node; import org.

Your Answer

Will server environment variables store iOS user-agent strings? The best way to stop people from exploiting that script especially if it's just for attachments you want people to download is just create a directory specifically for the attachments, and have it coded in your script ie, unchangable in the variables.

Fantastic job! ComponentContext; import javax. See this almost 5 years old bug report: Permalink to comment July 15,

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