Re: config.getInitParameter() still returning null
[EMAIL PROTECTED] wrote:
The config.getInitParameter() called from within a JSP page is
returning null. After changing the web.xml file numerous times and
trying all the suggestions from java.sun.com and the tomcat archives I
still cannot resolve this problem.
Does anyone know why we can't access the init parameters?
thanks in advance
Here is what my web.xml file looks like (does not work):
web-app
servlet
servlet-name
Error
/servlet-name
servlet-class
org.apache.jasper.runtime.JspServlet
/servlet-class
init-param
param-namedebug/param-name
param-valuetrue/param-value
/init-param
/servlet
/web-app
and my JSP code:
%
String s = config.getInitParameter("debug");
if (s == null) {
out.println("Init param must be null!");
}
else{
out.println("Init param is "+s);
}
%
Hi :-) I didn't ever use jsp to get init parameters, but I guess
the reasons is: in your WEB_INF/web.xml, you only define
a servlet definition with some init parameters, but you didn't
define a servlet-mapping; and/so I guess you invoked your
servlet without url-pattern(servlet-mapping name) - I guess
you use: http://localhost:8080/myapp/servlet/Myservlet ,
so if you use Servlet, the following will return null:
- config.getInitParameter(...)
- this.getInitParameter(...)
I suggest you:
- in WEB_INF/web.xml, when you define a servlet definition
with some init parameters, At the same time define a
servlet-mapping
- then use url-pattern to invoke your Servlet:
http://localhost:8080/myapp/XXX (XXX is url-pattern)
- if you don't want to define a servlet-definition and servlet-mapping
Pair in WEB-INF/web.xml, you also can define init parameters
in servlet context definition in conf/server.xml, and get them in
your servlet with the following way:
this.getServletContext().getInitParameter(...)
Bo
Mar.08, 2001
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Re: config.getInitParameter() still returning null
On Thu, 8 Mar 2001, Bo Xu wrote:
[EMAIL PROTECTED] wrote:
The config.getInitParameter() called from within a JSP page is
returning null. After changing the web.xml file numerous times and
trying all the suggestions from java.sun.com and the tomcat archives I
still cannot resolve this problem.
Does anyone know why we can't access the init parameters?
thanks in advance
Here is what my web.xml file looks like (does not work):
web-app
servlet
servlet-name
Error
/servlet-name
servlet-class
org.apache.jasper.runtime.JspServlet
/servlet-class
init-param
param-namedebug/param-name
param-valuetrue/param-value
/init-param
/servlet
/web-app
and my JSP code:
%
String s = config.getInitParameter("debug");
if (s == null) {
out.println("Init param must be null!");
}
else{
out.println("Init param is "+s);
}
%
Hi :-) I didn't ever use jsp to get init parameters, but I guess
the reasons is: in your WEB_INF/web.xml, you only define
a servlet definition with some init parameters, but you didn't
define a servlet-mapping; and/so I guess you invoked your
servlet without url-pattern(servlet-mapping name) - I guess
you use: http://localhost:8080/myapp/servlet/Myservlet ,
so if you use Servlet, the following will return null:
- config.getInitParameter(...)
- this.getInitParameter(...)
[ ... ]
I could be wrong, but I don't believe you have to define
servlet-mapping's to get init-param's to work, just having defined the
servlet is sufficient. However, in the URL, you do need to use the
specific servlet-name you used in the servlet definition. (That's
because you can define the same servlet class multiple times, with
different servlet-name's and different init-param's.)
So, according to the above web.xml, the URL that should be used is:
http://your.domain.com/yourwebappname/servlet/Error
(No, I haven't tested this.)
However, I just noticed that the original poster said that this is all
happening in a JSP ("JSP page" is redundant :-) -- that throws a
monkey wrench into the situation, and I'm not sure how it changes
things. For example, I don't know how to set up init-param's in a
JSP. Also, upon re-reading the above servlet definition, I'm not sure
that's the right way to set up a JSP -- i.e. putting
org.apache.jasper.runtime.JspServlet as the servlet-class (I assume
that's the tomcat/jasper servlet that handles JSP's). I think you
want to name your JSP something.jsp, and just tell tomcat somewhere
that it's a JSP. But again, I'm not sure how you'd set up
init-param's for it (maybe you do have to fallback on the suggestion
to use context init-param's, instead of servlet init-param's).
Well, I think I may have just raised more confusion, but perhaps this
will lead to some helpful discussion/ideas, and/or someone will post
clearing things up.
...
Hold on. I decided to do a google newsgroup search on this, to see if
I can get more definite information, and looks like I found the
answers. Check out the following posts:
http://groups.google.com/groups?q=init-param+jsphl=enlr=safe=offrnum=1seld=964886773ic=1
http://groups.google.com/groups?hl=enlr=safe=offth=9eb4e0cd3b0f1fb6rnum=9seld=958627636ic=1
Actually, I don't know if these URLs will work outside the context of
my search -- if not, go to the google advanced newsgroups search page
at:
http://groups.google.com/advanced_group_search
and enter "init-param jsp" in the "with all of the words" box (without
the quotes) and "hanna" in the "Author" box (again, without the
quotes).
Basically, it looks like a servlet definition can specify *either*
servlet-class or a jsp-file (those are the actual names of the tags
used in web.xml). Note the warnings about what form of URL to use
when you set things up this way, though.
Milt Epstein
Research Programmer
Software/Systems Development Group
Computing and Communications Services Office (CCSO)
University of Illinois at Urbana-Champaign (UIUC)
[EMAIL PROTECTED]
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
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Re: config.getInitParameter() still returning null
Milt Epstein wrote: [ ... ] I could be wrong, but I don't believe you have to define servlet-mapping's to get init-param's to work, just having defined the servlet is sufficient. However, in the URL, you do need to use the specific servlet-name you used in the servlet definition. (That's because you can define the same servlet class multiple times, with different servlet-name's and different init-param's.) So, according to the above web.xml, the URL that should be used is: http://your.domain.com/yourwebappname/servlet/Error [...] thanks for your email :-) and now I find mistake in my last email, the following is my new understanding about Servlet(not JSP) with jakarta-tomcat-4.0-b1 : 0 if we don't define any "named" servlet definition in webapps/myapp/WEB-INF/web.xml, then we can invoke MyServlet with the following way: http://localhost:8080/myapp/servlet/MyServlet it will invoke the "default/non-named" servlet definition 1 if we define the following in webapps/myapp/WEB-INF/web.xml: ... servlet-nameMyServlet_sn /servlet-name ... then we Also can invoke this servlet definition with this servlet-name: http://localhost:8080/myapp/servlet/MyServlet_sn 2 if we also define a servlet-mapping: servlet-mapping servlet-nameMyServlet_sn /servlet-name url-pattern /MyServlet_up/url-pattern /servlet-mapping then we Also can invoke this servlet definition with this url-pattern: http://localhost:8080/myapp/MyServlet_up and 1 and 2 will invoke the same "named" servlet definition whose name is MyServlet_sn. 3 from a email in "List.this" ^_^ , I find: if we directly use "MyServlet" as the servlet-name, and we invoke with the following way: http://localhost:8080/myapp/servlet/MyServlet we will goto that "named" servlet definition whose name is "MyServlet"- we will Not goto that "default/non-named" servlet definition. hope the above is right, otherwise I need to correct my "experience notebook" Again :-) or I need to use a pencial instead of a pen? :-) Bo Mar.08, 2001 - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
Re: config.getInitParameter() still returning null
Just to clear up what i'm trying to do: not having any problems getting init parameters using servlets, the following code in web.xml will achieve that: servlet servlet-nameMyServlet/servlet-name servlet-classMyServlet/servlet-class init-param param-namedebug/param-name param-valuetrue/param-value /init-param /servlet The problem is accessing init-params exclusively in JSPs without any servlets at all. In theory this should be possible as a JSP is a servlet but it's proving very difficult to do this. Right now i'm working on a background servlet for the JSP to make these init-params possible. I'll post solution when it's done. Bo Xu [EMAIL PROTECTED] 03/08/01 10:09 AM Please respond to tomcat-user To:[EMAIL PROTECTED] cc: Subject:Re: config.getInitParameter() still returning null Milt Epstein wrote: [ ... ] I could be wrong, but I don't believe you have to define servlet-mapping's to get init-param's to work, just having defined the servlet is sufficient. However, in the URL, you do need to use the specific servlet-name you used in the servlet definition. (That's because you can define the same servlet class multiple times, with different servlet-name's and different init-param's.) So, according to the above web.xml, the URL that should be used is: http://your.domain.com/yourwebappname/servlet/Error [...] thanks for your email :-) and now I find mistake in my last email, the following is my new understanding about Servlet(not JSP) with jakarta-tomcat-4.0-b1 : 0 if we don't define any named servlet definition in webapps/myapp/WEB-INF/web.xml, then we can invoke MyServlet with the following way: http://localhost:8080/myapp/servlet/MyServlet it will invoke the default/non-named servlet definition 1 if we define the following in webapps/myapp/WEB-INF/web.xml: ... servlet-nameMyServlet_sn /servlet-name ... then we Also can invoke this servlet definition with this servlet-name: http://localhost:8080/myapp/servlet/MyServlet_sn 2 if we also define a servlet-mapping: servlet-mapping servlet-nameMyServlet_sn /servlet-name url-pattern /MyServlet_up/url-pattern /servlet-mapping then we Also can invoke this servlet definition with this url-pattern: http://localhost:8080/myapp/MyServlet_up and 1 and 2 will invoke the same named servlet definition whose name is MyServlet_sn. 3 from a email in List.this ^_^ , I find: if we directly use MyServlet as the servlet-name, and we invoke with the following way: http://localhost:8080/myapp/servlet/MyServlet we will goto that named servlet definition whose name is MyServlet- we will Not goto that default/non-named servlet definition. hope the above is right, otherwise I need to correct my experience notebook Again :-) or I need to use a pencial instead of a pen? :-) Bo Mar.08, 2001 - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
solved-Re: config.getInitParameter() still returning null
OK this is how to get init-params working for JSP
Include this in your web.xml file
web-app
context-param
param-name
foo
/param-name
param-value
bar
/param-value
/context-param
/web-app
And then in your JSP page:
String s = application.getInitParameter(foo);
Milt Epstein [EMAIL PROTECTED]
03/08/01 08:00 AM
Please respond to tomcat-user
To:[EMAIL PROTECTED]
cc:
Subject:Re: config.getInitParameter() still returning null
On Thu, 8 Mar 2001, Bo Xu wrote:
[EMAIL PROTECTED] wrote:
The config.getInitParameter() called from within a JSP page is
returning null. After changing the web.xml file numerous times and
trying all the suggestions from java.sun.com and the tomcat archives I
still cannot resolve this problem.
Does anyone know why we can't access the init parameters?
thanks in advance
Here is what my web.xml file looks like (does not work):
web-app
servlet
servlet-name
Error
/servlet-name
servlet-class
org.apache.jasper.runtime.JspServlet
/servlet-class
init-param
param-namedebug/param-name
param-valuetrue/param-value
/init-param
/servlet
/web-app
and my JSP code:
%
String s = config.getInitParameter(debug);
if (s == null) {
out.println(Init param must be null!);
}
else{
out.println(Init param is +s);
}
%
Hi :-) I didn't ever use jsp to get init parameters, but I guess
the reasons is: in your WEB_INF/web.xml, you only define
a servlet definition with some init parameters, but you didn't
define a servlet-mapping; and/so I guess you invoked your
servlet without url-pattern(servlet-mapping name) - I guess
you use: http://localhost:8080/myapp/servlet/Myservlet ,
so if you use Servlet, the following will return null:
- config.getInitParameter(...)
- this.getInitParameter(...)
[ ... ]
I could be wrong, but I don't believe you have to define
servlet-mapping's to get init-param's to work, just having defined the
servlet is sufficient. However, in the URL, you do need to use the
specific servlet-name you used in the servlet definition. (That's
because you can define the same servlet class multiple times, with
different servlet-name's and different init-param's.)
So, according to the above web.xml, the URL that should be used is:
http://your.domain.com/yourwebappname/servlet/Error
(No, I haven't tested this.)
However, I just noticed that the original poster said that this is all
happening in a JSP (JSP page is redundant :-) -- that throws a
monkey wrench into the situation, and I'm not sure how it changes
things. For example, I don't know how to set up init-param's in a
JSP. Also, upon re-reading the above servlet definition, I'm not sure
that's the right way to set up a JSP -- i.e. putting
org.apache.jasper.runtime.JspServlet as the servlet-class (I assume
that's the tomcat/jasper servlet that handles JSP's). I think you
want to name your JSP something.jsp, and just tell tomcat somewhere
that it's a JSP. But again, I'm not sure how you'd set up
init-param's for it (maybe you do have to fallback on the suggestion
to use context init-param's, instead of servlet init-param's).
Well, I think I may have just raised more confusion, but perhaps this
will lead to some helpful discussion/ideas, and/or someone will post
clearing things up.
...
Hold on. I decided to do a google newsgroup search on this, to see if
I can get more definite information, and looks like I found the
answers. Check out the following posts:
http://groups.google.com/groups?q=init-param+jsphl=enlr=safe=offrnum=1seld=964886773ic=1
http://groups.google.com/groups?hl=enlr=safe=offth=9eb4e0cd3b0f1fb6rnum=9seld=958627636ic=1
Actually, I don't know if these URLs will work outside the context of
my search -- if not, go to the google advanced newsgroups search page
at:
http://groups.google.com/advanced_group_search
and enter init-param jsp in the with all of the words box (without
the quotes) and hanna in the Author box (again, without the
quotes).
Basically, it looks like a servlet definition can specify *either*
servlet-class or a jsp-file (those are the actual names of the tags
used in web.xml). Note the warnings about what form of URL to use
when you set things up this way, though.
Milt Epstein
Research Programmer
Software/Systems Development Group
Computing and Communications Services Office (CCSO)
University of Illinois at Urbana-Champaign (UIUC)
[EMAIL PROTECTED]
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, email: [EMAIL PROTECTED]
Re: solved-Re: config.getInitParameter() still returning null
On Thu, 8 Mar 2001 [EMAIL PROTECTED] wrote:
OK this is how to get init-params working for JSP
Include this in your web.xml file
web-app
context-param
param-name
foo
/param-name
param-value
bar
/param-value
/context-param
/web-app
And then in your JSP page:
String s = application.getInitParameter("foo");
[ ... ]
I'm sorry, but I must object :-). This isn't how to get init-param's
working with JSP, so it's not a solution -- and I wouldn't even call
it a workaround, because you don't need to do a workaround. What I
said in a previous note should work. I constructed an example to
demonstrate it.
Here's the relevant stuff from the web.xml file (which is located in
path-to-tomcat/webapps/blah/WEB-INF/):
servlet
servlet-nametesty/servlet-name
jsp-filetesty.jsp/jsp-file
init-param
param-namevar1/param-name
param-valuevalue1/param-value
/init-param
init-param
param-namevar2/param-name
param-valuevalue2/param-value
/init-param
/servlet
servlet-mapping
servlet-nametesty/servlet-name
url-pattern/testy.jsp/url-pattern
/servlet-mapping
I've appended the JSP after my sig.
I used a URL of the form:
http://my.domain.com/blah/testy.jsp
The only thing I had trouble with was where the test.jsp file should
go. I tried it in path-to-tomcat/webapps/blah/WEB-INF/classes/, and
it didn't work. I put it in path-to-tomcat/webapps/blah/, and it
did work. I'm not sure I fully understand why that is, but at least I
did get the init-param's working.
Milt Epstein
Research Programmer
Software/Systems Development Group
Computing and Communications Services Office (CCSO)
University of Illinois at Urbana-Champaign (UIUC)
[EMAIL PROTECTED]
HTML
HEAD
TITLETesty/TITLE
/HEAD
BODY
%@ page
import="java.util.*"
%
%!
Enumeration names;
String name;
%
P
The value of init parameter var1 is:
%=
getServletConfig().getInitParameter("var1")
%
/P
P
The init parameters are:
UL
%
names = getServletConfig().getInitParameterNames();
while (names.hasMoreElements()) {
name = (String) names.nextElement();
%
LI
%=
name
%
=
%=
getServletConfig().getInitParameter(name)
%
%
}
%
/UL
/P
/BODY
/HTML
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Re: solved-Re: config.getInitParameter() still returning null
On Thu, 8 Mar 2001, Milt Epstein wrote:
[ ... ]
HTML
HEAD
TITLETesty/TITLE
/HEAD
BODY
%@ page
import="java.util.*"
%
%!
Enumeration names;
String name;
%
P
The value of init parameter var1 is:
%=
getServletConfig().getInitParameter("var1")
%
/P
P
The init parameters are:
UL
%
names = getServletConfig().getInitParameterNames();
while (names.hasMoreElements()) {
name = (String) names.nextElement();
%
LI
%=
name
%
=
%=
getServletConfig().getInitParameter(name)
%
%
}
%
/UL
/P
/BODY
/HTML
BTW, it still works if I substitute "config" for "getServletConfig()"
everywhere above.
Milt Epstein
Research Programmer
Software/Systems Development Group
Computing and Communications Services Office (CCSO)
University of Illinois at Urbana-Champaign (UIUC)
[EMAIL PROTECTED]
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Re: solved-Re: config.getInitParameter() still returning null
Hello Milt
The value of init parameter var1 is:
%=
getServletConfig().getInitParameter("var1")
%
/P
I use this:
title%= getServletContext().getInitParameter("ApplicationName") %
instead of getServletConfig() and it works.
Markus
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Re: solved-Re: config.getInitParameter() still returning null
On Fri, 9 Mar 2001, Markus Keller [OrcaSoft] wrote:
Hello Milt
The value of init parameter var1 is:
%=
getServletConfig().getInitParameter("var1")
%
/P
I use this:
title%= getServletContext().getInitParameter("ApplicationName") %
instead of getServletConfig() and it works.
Well, they're not really interchangable, they're meant for different
purposes. Basically, according to the 2.2 spec, there are context
parameters, and servlet parameters. A context is basically a web
application, so context parameters are intended to be use for
application-wide parameters. Servlet parameters are only for a
specific servlet (i.e. a subset of the application).
Sure, you can avoid using servlet parameters, and only use context
parameters, but whether that's the most appropriate and/or cleanest
way to do things depends on what you're doing.
Milt Epstein
Research Programmer
Software/Systems Development Group
Computing and Communications Services Office (CCSO)
University of Illinois at Urbana-Champaign (UIUC)
[EMAIL PROTECTED]
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
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config.getInitParameter() still returning null
The config.getInitParameter() called from within a JSP page is returning null. After changing the web.xml file numerous times and trying all the suggestions from java.sun.com and the tomcat archives I still cannot resolve this problem.
Does anyone know why we can't access the init parameters?
thanks in advance
Here is what my web.xml file looks like (does not work):
web-app
servlet
servlet-name
Error
/servlet-name
servlet-class
org.apache.jasper.runtime.JspServlet
/servlet-class
init-param
param-namedebug/param-name
param-valuetrue/param-value
/init-param
/servlet
/web-app
and my JSP code:
%
String s = config.getInitParameter(debug);
if (s == null) {
out.println(Init param must be null!);
}
else{
out.println(Init param is +s);
}
%
Re: config.getInitParameter() still returning null
Hi,
Murphy
I used
the methodconfig.getInitParameterNames() to get theEnumeration
(pa) ofparameters.
then I
printed them out like this:
while
(pa.hasMoreElements()) {
String key = (String)
pa.nextElement();
String value =
config.getInitParameter(key);
out.println(key + " : " + value +
"br");
}
the
result is:
logVerbosityLevel : WARNING
javaEncoding : UTF-8
that
didn't the key and value i think you wanna retrieve.
So if you
want get the Initiate parameters of one specific servlet, in my view, you should
use this method only in the servlet itself. Let's suppose that you had defined
two servlet in your web.xml file. when you get the initparameters, I want to
ask, which servlet did these parameters belong to.
think it
would help.
J.
Chen
--: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]: 200138
8:17: [EMAIL PROTECTED]:
config.getInitParameter() still returning nullThe config.getInitParameter() called from within a
JSP page is returning null. After changing the web.xml file numerous times and
trying all the suggestions from java.sun.com and the tomcat archives I still
cannot resolve this problem. Does
anyone know why we can't access the init parameters? thanks in advance Here is what my web.xml file looks like (does not
work): web-app
servlet
servlet-name
Error /servlet-name
servlet-class
org.apache.jasper.runtime.JspServlet
/servlet-class
init-param
param-namedebug/param-name
param-valuetrue/param-value
/init-param
/servlet /web-app and my JSP
code: % String s = config.getInitParameter("debug");
if (s == null) { out.println("Init param must be null!");
} else{ out.println("Init param
is "+s); } %
