How do you add a http protocol header value in HttpServletRequest ？

Question

How do you add a http protocol header value in HttpServletRequest at a Filter，before call request.getHeader() and get the header value?

Answer 1

You can find the hooks in HttpServletRequestWrapper.

[Edited to include a link to an example]

Here you can find a fine example.

Answer 2

HttpServletRequest objects are read-only. You cannot modify them. But you can definitely extend their functionality by employing a decorator pattern and add mutability in the extended class. Take a look at the following post:

http://wilddiary.com/adding-custom-headers-java-httpservletrequest/