It is purely a static class, it cannot be instantiated. Returns true if the request contains the named extra header. Gets the value of the named request extra header, or null if it is not present. For HTTP, this is GET , POST , etc. May be used to construct self-referencing URLs.
Returns null if no extra path information was present.
This method retrieves any such extra path information as translated from URL to physical form. Returns null if no extra path information was present. The misspelling is historical. Returns true if the request contains the named extra header. The enumeration returns String objects that contain the header name or label of a request extra header.