It's important to remember that the Servlet Specification target
audience isn't application developers -- it's people that are
implementing servlet containers (such as the group that creates
Tomcat). It is about defining requirements, not illustrating use
cases.
For application level questions, and especially for beginners, you'll
find any of the plethora of books, magazine articles, tutorials, and
mailing lists that are available to be somewhat more accessible.
(Personally, I still agree with your PS about the spec being "required
reading" -- just need to set your expectations correctly :-).
As for your specific question about accessing a context init
parameter, you do have it right.
Craig
On Wed, 24 Nov 2004 14:26:23 -0500, Erik Weber <[EMAIL PROTECTED]> wrote:
> Well, I have to criticize my own advice. I just read over the Servlet
> 2.4 spec. It doesn't explain this well at all, in my opinion. It still
> uses the same old, nearly meaningless, obscure language like "used by
> the Servlet container to communicate with a Servlet", and stuff like
> that, which doesn't help anyone who actually wants to write a program.
> It does mention the getInitParameter methods of ServletContext and
> ServletConfig, but nowhere that I could find does it simply say, use one
> with this element in web.xml and the other with that element in web.xml,
> and/or why you would choose one or the other.
>
> Why can't the spec just say what I wrote below instead of trying to be
> so "conceptual"? Is what I wrote wrong? This is the stuff that .NET
> people criticize and that frustrates new programmers (in my experience).
>
> Here is a partial outline of how it should be explained:
>
> Initializing a Servlet
> -------------------------
>
> I. Initialization parameter that is global to your Web application (all
> Servlets)
>
> A. web.xml
>
> <web-app>
> . . .
> <context-param>
> <param-name>globalDateFormatString</param-name>
> <param-value>yyyy-MM-dd</param-value>
> </context-param>
> . . .
> </web-app>
>
> B. Java
>
> // store the date format String, but not a DateFormat,
> // as an instance variable or class variable
> // (DateFormat can't always be used concurrently)
> protected String globalDateFormatString;
> . . .
> public void init() throws ServletException, UnavailableException {
> globalDateFormatString =
> getServletContext().getInitParameter("globalDateFormatString");
> // try to instantiate a SimpleDateFormat with the String;
> // if the String is invalid, throw an Exception to make the Servlet
> unavailable
> }
>
> II. Initialization parameter that is specific to one Servlet
>
> A. web.xml
>
> <servlet>
> . . .
> <init-param>
> <param-name>specificDateFormatString</param-name>
> <param-value>|EEE, d MMM yyyy HH:mm:ss Z|</param-value>
> </init-param>
> . . .
> </servlet>
>
> B. Java
>
> protected String specificDateFormatString;
> . . .
> public void init() throws ServletException, UnavailableException {
> globalDateFormatString =
> getServletConfig().getInitParameter("specificDateFormatString");
> }
>
> Please correct me if I have it wrong, or show me the light if I missed
> something in the spec. I know I learned this somewhere, but can't
> remember where (the tutorial maybe?).
>
> Shouldn't this be the way the spec reads, or does this type of example
> belong somewhere else?
>
> Erik
>
> P.S. The spec is still required reading. ;-)
>
>
>
>
> Bill Siggelkow wrote:
>
> > Thanks for the clarification, Erik.
> >
> > Erik Weber wrote:
> >
> >> I think you want ServletContext.getInitParameter here. That is used
> >> with the "context-param" element (global to your web app).
> >> ServletConfig.getInitParameter is used with the "init-param" element
> >> (specific to one Servlet).
> >>
> >> In addition to the JavaDocs, you should read the Servlet
> >> specification, which tells you how Servlets and Servlet containers
> >> are supposed to work. Trust me, it is required reading:
> >>
> >> http://www.jcp.org/aboutJava/communityprocess/final/jsr154/
> >>
> >> Erik
> >>
> >>
> >>
> >>
> >> Bill Siggelkow wrote:
> >>
> >>> MyServlet extends HttpServlet {
> >>> public void init (ServletConfig config) {
> >>> String paramValue = config.getInitParameter("myContextParamName");
> >>> }
> >>> }
> >>>
> >>> Personally, I have found the JavaDocs invaluable for this kind of
> >>> stuff; you can find the Servlet 2.4 Javadocs online at
> >>> http://jakarta.apache.org/tomcat/tomcat-5.0-doc/servletapi/index.html.
> >>>
> >>> -Bill Siggelkow
> >>>
> >>> Nishant wrote:
> >>>
> >>>> hi
> >>>> can anyone tell me how can i get context-param parameter in my
> >>>> servlet .
> >>>> thanks in advance
> >>>> Regards
> >>>> Nishant Patil
> >>>> Software Engineer
> >>>> Cybage Softwares Pvt. Ltd. (A CMM Level 3 Company)
> >>>> West Avenue, Kalyaninagar
> >>>> Pune - 411006
> >>>> Ph. +91-20-4044700/4041700 Extn 355
> >>>> [EMAIL PROTECTED]
> >>>> www.cybage.com
> >>>> "There is difference between knowing the Path and walking on the Path"
> >>>
> >>>
> >>>
> >>>
> >>>
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> >>>
> >>>
> >
> >
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> >
>
>
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