How to check whether HttpServletRequest contains the key in Java (Using spring boot)

Question

HttpServletRequest httpReq = (HttpServletRequest) request;

if (httpReq.getHeader("device").equals("web1")) {
    chain.doFilter(request, response);
}

I want to know how can I check whether the key "device" exists in the request header?

Note : Don't want to use getHeaderName which returns an enumeration of all the header names this request contains and iterate through it.

getParameterMap().containsKey("device") is not working here.

Answer 1

From the JavaDoc for HttpServletRequest.getHeader(String name):

If the request did not include a header of the specified name, this method returns null.

So a basic null check is sufficient:

boolean deviceHeaderExists = httpReq.getHeader("device") != null;

Answer 2

Reading between the lines a little, if you're looking to accept a mandatory device header then you can code that up with annotations in your REST call. Example:

@GetMapping("/something")
public void doSomething(@RequestHeader("device") @NotNull String deviceName) {
  // your logic here
}