Re: do you get error in this url?
Lew wrote:
All you had to do was read the Javadocs for
HttpServletRequest#getHeader(String):
"Returns: a String containing the value of the requested header, or
null if the request does not have a header of that name."
maya wrote:
Lew, I did look in [the] Javadocs, I have looked in servlet API docs many
times and am quite familiar with it (esp[ecially] with [the] request obj[ect]), and I have
used this particular method very often and I had never had a problem
with it..
Take a look at that quote from the Javadocs again. Just because you "never'
had a problem with" ignoring that possibility doesn't mean you should ignore
that possibility, so clearly and explicitly documented.
Lew wrote:
This alerts you to the possibility that this "standard method" has
'null' as a "standard" return value, and this obligates you to deal
with that possibility, an obligation your code shirked and thus
engendered a bug.
Request headers are an external input to your program. Your program
does not control external inputs.
maya wrote:
I must say, I'm not sure what you mean by this.. most of these methods
I mean exactly what the words say - your code must account for all possible
inputs (or, in this case, return values), whether you experienced them before
or not. Your code doesn't control what comes from outside; it can only react
to what comes from outside.
of servlet API request obj[ect] return info sent from the request, either by
the user directly or from an env[ironment] variable; I simply didn't know you
could run into problems with these methods as I did in this case..
Then you didn't read the Javadocs. How in the world can a method return info
from a request that is not sent in the request?
Lew wrote:
You must deal with every possible
input from the outside, including no input at all.
maya wrote:
yes I know, I usu. do this, I simply had no idea that this particular
method could return a value of null, learned a lesson, I guess....;)
And yet the docs clearly state that this particular method can return a value
of 'null'.
--
Lew