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Posted to users@tomcat.apache.org by "Craig R. McClanahan" <cr...@apache.org> on 2002/07/09 18:20:38 UTC
Re: Tomcat 4 cross ServletContext attributes and standalone server
On Mon, 8 Jul 2002, dbt1 wrote:
> Date: Mon, 8 Jul 2002 10:31:31 -0600
> From: dbt1 <db...@dbgroups.com>
> Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> To: Tomcat Developers List <to...@jakarta.apache.org>,
> Struts Users Mailing List <st...@jakarta.apache.org>,
> tomcat-user@jakarta.apache.org
> Subject: Tomcat 4 cross ServletContext attributes and standalone server
>
> I curently have 2 issues and hope someone may quickly point me to the right
> solutions.
> Environment: Tomcat 4.03, Struts 1.1
>
> Issue 1: Tomcat standalone to serve other file types such as .pdf .ppt .doc
> Previously I use Apache as a web server connected to Tomcat 3.3 for jsp
> pages. URLs to the above file types work fine. Changing to Tomcat 4
> standalone, everything is great with jsp, but Tomcat web server does not
> recognize and serve the other file types. I expect appropriate setting of
> file types would sold this problem so Tomcat Standalone will be appropriate
> for mostly dynamic jsp site without using Apache and connectors.
>
What does "does not recognize and serve the other file types" mean? If
it's just an issue of getting the correct content type set, you can
configure that for yourself by using <mime-type> entries in web.xml --
either for your app itself, or for the entire Tomcat installation (edit
the file "$CATALINA_HOME/conf/web.xml" for those). If you are getting 404
errors, that means you don't have the files in the right place, or
something else is wrong.
> Issue 2: Using ServletContext attributes as global variables accross web
> applications within the same virtual host and across different virtual
> hosts. My arrangement is as follows:
>
> VirtualHost1/ROOT/mainApp
> /sub1/subApp1
> VirtualHost2/ etc.
>
> ServletContext attributes set in subApp1 are alive and available to subApp1.
> >From mainApp, I need to get attributes in subApp1. From mainApp, I access
> Struts 1.1 ActionServlet and get to its ServletContext
> (getServlet().getServletContext()). From mainApp ServletContext, I get to
> subApp1 ServletContext with getContext("/subApp1") and to get the required
> attributes of subApp1, which I know they are there and not null as tested
> from subApp1 ServletContext. The whole code is:
>
> (MyPlugIn) myPlugIn = (MyPlugIn)
> ((getServlet().getServletContext()).getContext("/subApp1")).getAttribute(myP
> lugIn);
>
> This line of code gives null value from both mainApp and subApp1
> ServletContext. I did explicitly set appropriate docBase and
> crossContext="true" for both mainApp and subApp1 in tomcat4 server.xml
>
This sounds like an issue that should be reported against Tomcat.
> The question are:
> 1) How do I get global variables across web applications within 1
> virtual host and across virtual hosts using Tomcat 4 container?
> 2) Is there a better method for sharing global variables across web
> applications within the same virtual host, and across virtual hosts in the
> same server?
One option is to put the relevant classes in Tomcat's common/lib
directory, and make the appropriate information available through some
static method (such as a factory pattern). Such statics are shared across
all virtual hosts and all webapps in a single Tomcat instance.
> 3) What is the best approach to scale from the above scenario to
> distributed environment?
Store the shared stuff in a database, EJB, LDAP server, or some other
external resource.
> 4) If Ldap is used for global variable distributed environment, what is
> the best design for mostly read and few updates of JavaBeans to Ldap, both
> for performance and security.
>
Most LDAP servers are optimized for read performance already. If that's
not fast enough, consider caching the retrieved information in servlet
context attributes in each webapp -- keeping in mind that you will need
some technique to ensure that updates get propogated in a timely manner.
> Any help is greatly appreciated. Thanks.
>
Craig
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
Re: Tomcat 4 cross ServletContext attributes and standalone server
Posted by "Craig R. McClanahan" <cr...@apache.org>.
On Tue, 9 Jul 2002, dbt1 wrote:
> Date: Tue, 9 Jul 2002 14:32:52 -0600
> From: dbt1 <db...@dbgroups.com>
> Reply-To: Tomcat Developers List <to...@jakarta.apache.org>
> To: tomcat-dev@jakarta.apache.org, tomcat-user@jakarta.apache.org
> Subject: Re: Tomcat 4 cross ServletContext attributes and standalone
> server
>
> Thanks Craig. Is any tomcat user has encountered these problems and have
> solutions. To recap:
>
> 1) I check file extension in tomcat/config/web.xml and see both .doc and
> .pdf file extensions. A link to these files with correct path (tested with
> .pdf, .doc, .ppt)
> (e.g. /WEB-INF/do/public/info/myFile.pdf) give me 404 resource not available
> error. Environment: RH Linux 7.2, tomcat 4.03 (and 4.1.7), struts 1.1, jdk
> 1.4
>
At least for this sample of a path, the answer is obvious -- the servlet
spec prohibits containers from serving static resources under the /WEB-INF
directory, which Tomcat implements by returning a 404. Move your PDF file
somewhere else in the webapp and you should be fine.
> 2) Tomcat 4 does not see the cross ServletContext attributes from mainApp to
> subApp1. Both contexts have crossContext="true"
I haven't experimented with this for quite a while, so don't know the
current status.
Craig
>
>
> ----- Original Message -----
> From: "Craig R. McClanahan" <cr...@apache.org>
> To: "Struts Users Mailing List" <st...@jakarta.apache.org>
> Cc: "Tomcat Developers List" <to...@jakarta.apache.org>;
> <to...@jakarta.apache.org>
> Sent: Tuesday, July 09, 2002 10:20 AM
> Subject: Re: Tomcat 4 cross ServletContext attributes and standalone server
>
>
> >
> >
> > On Mon, 8 Jul 2002, dbt1 wrote:
> >
> > > Date: Mon, 8 Jul 2002 10:31:31 -0600
> > > From: dbt1 <db...@dbgroups.com>
> > > Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> > > To: Tomcat Developers List <to...@jakarta.apache.org>,
> > > Struts Users Mailing List <st...@jakarta.apache.org>,
> > > tomcat-user@jakarta.apache.org
> > > Subject: Tomcat 4 cross ServletContext attributes and standalone server
> > >
> > > I curently have 2 issues and hope someone may quickly point me to the
> right
> > > solutions.
> > > Environment: Tomcat 4.03, Struts 1.1
> > >
> > > Issue 1: Tomcat standalone to serve other file types such as .pdf .ppt
> .doc
> > > Previously I use Apache as a web server connected to Tomcat 3.3 for jsp
> > > pages. URLs to the above file types work fine. Changing to Tomcat 4
> > > standalone, everything is great with jsp, but Tomcat web server does not
> > > recognize and serve the other file types. I expect appropriate setting
> of
> > > file types would sold this problem so Tomcat Standalone will be
> appropriate
> > > for mostly dynamic jsp site without using Apache and connectors.
> > >
> >
> > What does "does not recognize and serve the other file types" mean? If
> > it's just an issue of getting the correct content type set, you can
> > configure that for yourself by using <mime-type> entries in web.xml --
> > either for your app itself, or for the entire Tomcat installation (edit
> > the file "$CATALINA_HOME/conf/web.xml" for those). If you are getting 404
> > errors, that means you don't have the files in the right place, or
> > something else is wrong.
> >
> > > Issue 2: Using ServletContext attributes as global variables accross web
> > > applications within the same virtual host and across different virtual
> > > hosts. My arrangement is as follows:
> > >
> > > VirtualHost1/ROOT/mainApp
> > > /sub1/subApp1
> > > VirtualHost2/ etc.
> > >
> > > ServletContext attributes set in subApp1 are alive and available to
> subApp1.
> > > >From mainApp, I need to get attributes in subApp1. From mainApp, I
> access
> > > Struts 1.1 ActionServlet and get to its ServletContext
> > > (getServlet().getServletContext()). From mainApp ServletContext, I get
> to
> > > subApp1 ServletContext with getContext("/subApp1") and to get the
> required
> > > attributes of subApp1, which I know they are there and not null as
> tested
> > > from subApp1 ServletContext. The whole code is:
> > >
> > > (MyPlugIn) myPlugIn = (MyPlugIn)
> > >
> ((getServlet().getServletContext()).getContext("/subApp1")).getAttribute(myP
> > > lugIn);
> > >
> > > This line of code gives null value from both mainApp and subApp1
> > > ServletContext. I did explicitly set appropriate docBase and
> > > crossContext="true" for both mainApp and subApp1 in tomcat4 server.xml
> > >
> >
> > This sounds like an issue that should be reported against Tomcat.
> >
> > > The questions are:
> > > 1) How do I get global variables across web applications within 1
> > > virtual host and across virtual hosts using Tomcat 4 container?
> > > 2) Is there a better method for sharing global variables across web
> > > applications within the same virtual host, and across virtual hosts in
> the
> > > same server?
> >
> > One option is to put the relevant classes in Tomcat's common/lib
> > directory, and make the appropriate information available through some
> > static method (such as a factory pattern). Such statics are shared across
> > all virtual hosts and all webapps in a single Tomcat instance.
> >
> > > 3) What is the best approach to scale from the above scenario to
> > > distributed environment?
> >
> > Store the shared stuff in a database, EJB, LDAP server, or some other
> > external resource.
> >
> > > 4) If Ldap is used for global variable distributed environment, what
> is
> > > the best design for mostly read and few updates of JavaBeans to Ldap,
> both
> > > for performance and security.
> > >
> >
> > Most LDAP servers are optimized for read performance already. If that's
> > not fast enough, consider caching the retrieved information in servlet
> > context attributes in each webapp -- keeping in mind that you will need
> > some technique to ensure that updates get propogated in a timely manner.
> >
> > > Any help is greatly appreciated. Thanks.
> > >
> >
> > Craig
> >
> >
> > --
> > To unsubscribe, e-mail:
> <ma...@jakarta.apache.org>
> > For additional commands, e-mail:
> <ma...@jakarta.apache.org>
> >
>
>
> --
> To unsubscribe, e-mail: <ma...@jakarta.apache.org>
> For additional commands, e-mail: <ma...@jakarta.apache.org>
>
>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
Re: Tomcat 4 cross ServletContext attributes and standalone server
Posted by "Craig R. McClanahan" <cr...@apache.org>.
On Tue, 9 Jul 2002, dbt1 wrote:
> Date: Tue, 9 Jul 2002 14:32:52 -0600
> From: dbt1 <db...@dbgroups.com>
> Reply-To: Tomcat Developers List <to...@jakarta.apache.org>
> To: tomcat-dev@jakarta.apache.org, tomcat-user@jakarta.apache.org
> Subject: Re: Tomcat 4 cross ServletContext attributes and standalone
> server
>
> Thanks Craig. Is any tomcat user has encountered these problems and have
> solutions. To recap:
>
> 1) I check file extension in tomcat/config/web.xml and see both .doc and
> .pdf file extensions. A link to these files with correct path (tested with
> .pdf, .doc, .ppt)
> (e.g. /WEB-INF/do/public/info/myFile.pdf) give me 404 resource not available
> error. Environment: RH Linux 7.2, tomcat 4.03 (and 4.1.7), struts 1.1, jdk
> 1.4
>
At least for this sample of a path, the answer is obvious -- the servlet
spec prohibits containers from serving static resources under the /WEB-INF
directory, which Tomcat implements by returning a 404. Move your PDF file
somewhere else in the webapp and you should be fine.
> 2) Tomcat 4 does not see the cross ServletContext attributes from mainApp to
> subApp1. Both contexts have crossContext="true"
I haven't experimented with this for quite a while, so don't know the
current status.
Craig
>
>
> ----- Original Message -----
> From: "Craig R. McClanahan" <cr...@apache.org>
> To: "Struts Users Mailing List" <st...@jakarta.apache.org>
> Cc: "Tomcat Developers List" <to...@jakarta.apache.org>;
> <to...@jakarta.apache.org>
> Sent: Tuesday, July 09, 2002 10:20 AM
> Subject: Re: Tomcat 4 cross ServletContext attributes and standalone server
>
>
> >
> >
> > On Mon, 8 Jul 2002, dbt1 wrote:
> >
> > > Date: Mon, 8 Jul 2002 10:31:31 -0600
> > > From: dbt1 <db...@dbgroups.com>
> > > Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> > > To: Tomcat Developers List <to...@jakarta.apache.org>,
> > > Struts Users Mailing List <st...@jakarta.apache.org>,
> > > tomcat-user@jakarta.apache.org
> > > Subject: Tomcat 4 cross ServletContext attributes and standalone server
> > >
> > > I curently have 2 issues and hope someone may quickly point me to the
> right
> > > solutions.
> > > Environment: Tomcat 4.03, Struts 1.1
> > >
> > > Issue 1: Tomcat standalone to serve other file types such as .pdf .ppt
> .doc
> > > Previously I use Apache as a web server connected to Tomcat 3.3 for jsp
> > > pages. URLs to the above file types work fine. Changing to Tomcat 4
> > > standalone, everything is great with jsp, but Tomcat web server does not
> > > recognize and serve the other file types. I expect appropriate setting
> of
> > > file types would sold this problem so Tomcat Standalone will be
> appropriate
> > > for mostly dynamic jsp site without using Apache and connectors.
> > >
> >
> > What does "does not recognize and serve the other file types" mean? If
> > it's just an issue of getting the correct content type set, you can
> > configure that for yourself by using <mime-type> entries in web.xml --
> > either for your app itself, or for the entire Tomcat installation (edit
> > the file "$CATALINA_HOME/conf/web.xml" for those). If you are getting 404
> > errors, that means you don't have the files in the right place, or
> > something else is wrong.
> >
> > > Issue 2: Using ServletContext attributes as global variables accross web
> > > applications within the same virtual host and across different virtual
> > > hosts. My arrangement is as follows:
> > >
> > > VirtualHost1/ROOT/mainApp
> > > /sub1/subApp1
> > > VirtualHost2/ etc.
> > >
> > > ServletContext attributes set in subApp1 are alive and available to
> subApp1.
> > > >From mainApp, I need to get attributes in subApp1. From mainApp, I
> access
> > > Struts 1.1 ActionServlet and get to its ServletContext
> > > (getServlet().getServletContext()). From mainApp ServletContext, I get
> to
> > > subApp1 ServletContext with getContext("/subApp1") and to get the
> required
> > > attributes of subApp1, which I know they are there and not null as
> tested
> > > from subApp1 ServletContext. The whole code is:
> > >
> > > (MyPlugIn) myPlugIn = (MyPlugIn)
> > >
> ((getServlet().getServletContext()).getContext("/subApp1")).getAttribute(myP
> > > lugIn);
> > >
> > > This line of code gives null value from both mainApp and subApp1
> > > ServletContext. I did explicitly set appropriate docBase and
> > > crossContext="true" for both mainApp and subApp1 in tomcat4 server.xml
> > >
> >
> > This sounds like an issue that should be reported against Tomcat.
> >
> > > The questions are:
> > > 1) How do I get global variables across web applications within 1
> > > virtual host and across virtual hosts using Tomcat 4 container?
> > > 2) Is there a better method for sharing global variables across web
> > > applications within the same virtual host, and across virtual hosts in
> the
> > > same server?
> >
> > One option is to put the relevant classes in Tomcat's common/lib
> > directory, and make the appropriate information available through some
> > static method (such as a factory pattern). Such statics are shared across
> > all virtual hosts and all webapps in a single Tomcat instance.
> >
> > > 3) What is the best approach to scale from the above scenario to
> > > distributed environment?
> >
> > Store the shared stuff in a database, EJB, LDAP server, or some other
> > external resource.
> >
> > > 4) If Ldap is used for global variable distributed environment, what
> is
> > > the best design for mostly read and few updates of JavaBeans to Ldap,
> both
> > > for performance and security.
> > >
> >
> > Most LDAP servers are optimized for read performance already. If that's
> > not fast enough, consider caching the retrieved information in servlet
> > context attributes in each webapp -- keeping in mind that you will need
> > some technique to ensure that updates get propogated in a timely manner.
> >
> > > Any help is greatly appreciated. Thanks.
> > >
> >
> > Craig
> >
> >
> > --
> > To unsubscribe, e-mail:
> <ma...@jakarta.apache.org>
> > For additional commands, e-mail:
> <ma...@jakarta.apache.org>
> >
>
>
> --
> To unsubscribe, e-mail: <ma...@jakarta.apache.org>
> For additional commands, e-mail: <ma...@jakarta.apache.org>
>
>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
Re: Tomcat 4 cross ServletContext attributes and standalone server
Posted by dbt1 <db...@dbgroups.com>.
Thanks Craig. Is any tomcat user has encountered these problems and have
solutions. To recap:
1) I check file extension in tomcat/config/web.xml and see both .doc and
.pdf file extensions. A link to these files with correct path (tested with
.pdf, .doc, .ppt)
(e.g. /WEB-INF/do/public/info/myFile.pdf) give me 404 resource not available
error. Environment: RH Linux 7.2, tomcat 4.03 (and 4.1.7), struts 1.1, jdk
1.4
2) Tomcat 4 does not see the cross ServletContext attributes from mainApp to
subApp1. Both contexts have crossContext="true"
----- Original Message -----
From: "Craig R. McClanahan" <cr...@apache.org>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Cc: "Tomcat Developers List" <to...@jakarta.apache.org>;
<to...@jakarta.apache.org>
Sent: Tuesday, July 09, 2002 10:20 AM
Subject: Re: Tomcat 4 cross ServletContext attributes and standalone server
>
>
> On Mon, 8 Jul 2002, dbt1 wrote:
>
> > Date: Mon, 8 Jul 2002 10:31:31 -0600
> > From: dbt1 <db...@dbgroups.com>
> > Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> > To: Tomcat Developers List <to...@jakarta.apache.org>,
> > Struts Users Mailing List <st...@jakarta.apache.org>,
> > tomcat-user@jakarta.apache.org
> > Subject: Tomcat 4 cross ServletContext attributes and standalone server
> >
> > I curently have 2 issues and hope someone may quickly point me to the
right
> > solutions.
> > Environment: Tomcat 4.03, Struts 1.1
> >
> > Issue 1: Tomcat standalone to serve other file types such as .pdf .ppt
.doc
> > Previously I use Apache as a web server connected to Tomcat 3.3 for jsp
> > pages. URLs to the above file types work fine. Changing to Tomcat 4
> > standalone, everything is great with jsp, but Tomcat web server does not
> > recognize and serve the other file types. I expect appropriate setting
of
> > file types would sold this problem so Tomcat Standalone will be
appropriate
> > for mostly dynamic jsp site without using Apache and connectors.
> >
>
> What does "does not recognize and serve the other file types" mean? If
> it's just an issue of getting the correct content type set, you can
> configure that for yourself by using <mime-type> entries in web.xml --
> either for your app itself, or for the entire Tomcat installation (edit
> the file "$CATALINA_HOME/conf/web.xml" for those). If you are getting 404
> errors, that means you don't have the files in the right place, or
> something else is wrong.
>
> > Issue 2: Using ServletContext attributes as global variables accross web
> > applications within the same virtual host and across different virtual
> > hosts. My arrangement is as follows:
> >
> > VirtualHost1/ROOT/mainApp
> > /sub1/subApp1
> > VirtualHost2/ etc.
> >
> > ServletContext attributes set in subApp1 are alive and available to
subApp1.
> > >From mainApp, I need to get attributes in subApp1. From mainApp, I
access
> > Struts 1.1 ActionServlet and get to its ServletContext
> > (getServlet().getServletContext()). From mainApp ServletContext, I get
to
> > subApp1 ServletContext with getContext("/subApp1") and to get the
required
> > attributes of subApp1, which I know they are there and not null as
tested
> > from subApp1 ServletContext. The whole code is:
> >
> > (MyPlugIn) myPlugIn = (MyPlugIn)
> >
((getServlet().getServletContext()).getContext("/subApp1")).getAttribute(myP
> > lugIn);
> >
> > This line of code gives null value from both mainApp and subApp1
> > ServletContext. I did explicitly set appropriate docBase and
> > crossContext="true" for both mainApp and subApp1 in tomcat4 server.xml
> >
>
> This sounds like an issue that should be reported against Tomcat.
>
> > The questions are:
> > 1) How do I get global variables across web applications within 1
> > virtual host and across virtual hosts using Tomcat 4 container?
> > 2) Is there a better method for sharing global variables across web
> > applications within the same virtual host, and across virtual hosts in
the
> > same server?
>
> One option is to put the relevant classes in Tomcat's common/lib
> directory, and make the appropriate information available through some
> static method (such as a factory pattern). Such statics are shared across
> all virtual hosts and all webapps in a single Tomcat instance.
>
> > 3) What is the best approach to scale from the above scenario to
> > distributed environment?
>
> Store the shared stuff in a database, EJB, LDAP server, or some other
> external resource.
>
> > 4) If Ldap is used for global variable distributed environment, what
is
> > the best design for mostly read and few updates of JavaBeans to Ldap,
both
> > for performance and security.
> >
>
> Most LDAP servers are optimized for read performance already. If that's
> not fast enough, consider caching the retrieved information in servlet
> context attributes in each webapp -- keeping in mind that you will need
> some technique to ensure that updates get propogated in a timely manner.
>
> > Any help is greatly appreciated. Thanks.
> >
>
> Craig
>
>
> --
> To unsubscribe, e-mail:
<ma...@jakarta.apache.org>
> For additional commands, e-mail:
<ma...@jakarta.apache.org>
>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
Re: Tomcat 4 cross ServletContext attributes and standalone server
Posted by dbt1 <db...@dbgroups.com>.
Thanks Craig. Is any tomcat user has encountered these problems and have
solutions. To recap:
1) I check file extension in tomcat/config/web.xml and see both .doc and
.pdf file extensions. A link to these files with correct path (tested with
.pdf, .doc, .ppt)
(e.g. /WEB-INF/do/public/info/myFile.pdf) give me 404 resource not available
error. Environment: RH Linux 7.2, tomcat 4.03 (and 4.1.7), struts 1.1, jdk
1.4
2) Tomcat 4 does not see the cross ServletContext attributes from mainApp to
subApp1. Both contexts have crossContext="true"
----- Original Message -----
From: "Craig R. McClanahan" <cr...@apache.org>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Cc: "Tomcat Developers List" <to...@jakarta.apache.org>;
<to...@jakarta.apache.org>
Sent: Tuesday, July 09, 2002 10:20 AM
Subject: Re: Tomcat 4 cross ServletContext attributes and standalone server
>
>
> On Mon, 8 Jul 2002, dbt1 wrote:
>
> > Date: Mon, 8 Jul 2002 10:31:31 -0600
> > From: dbt1 <db...@dbgroups.com>
> > Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> > To: Tomcat Developers List <to...@jakarta.apache.org>,
> > Struts Users Mailing List <st...@jakarta.apache.org>,
> > tomcat-user@jakarta.apache.org
> > Subject: Tomcat 4 cross ServletContext attributes and standalone server
> >
> > I curently have 2 issues and hope someone may quickly point me to the
right
> > solutions.
> > Environment: Tomcat 4.03, Struts 1.1
> >
> > Issue 1: Tomcat standalone to serve other file types such as .pdf .ppt
.doc
> > Previously I use Apache as a web server connected to Tomcat 3.3 for jsp
> > pages. URLs to the above file types work fine. Changing to Tomcat 4
> > standalone, everything is great with jsp, but Tomcat web server does not
> > recognize and serve the other file types. I expect appropriate setting
of
> > file types would sold this problem so Tomcat Standalone will be
appropriate
> > for mostly dynamic jsp site without using Apache and connectors.
> >
>
> What does "does not recognize and serve the other file types" mean? If
> it's just an issue of getting the correct content type set, you can
> configure that for yourself by using <mime-type> entries in web.xml --
> either for your app itself, or for the entire Tomcat installation (edit
> the file "$CATALINA_HOME/conf/web.xml" for those). If you are getting 404
> errors, that means you don't have the files in the right place, or
> something else is wrong.
>
> > Issue 2: Using ServletContext attributes as global variables accross web
> > applications within the same virtual host and across different virtual
> > hosts. My arrangement is as follows:
> >
> > VirtualHost1/ROOT/mainApp
> > /sub1/subApp1
> > VirtualHost2/ etc.
> >
> > ServletContext attributes set in subApp1 are alive and available to
subApp1.
> > >From mainApp, I need to get attributes in subApp1. From mainApp, I
access
> > Struts 1.1 ActionServlet and get to its ServletContext
> > (getServlet().getServletContext()). From mainApp ServletContext, I get
to
> > subApp1 ServletContext with getContext("/subApp1") and to get the
required
> > attributes of subApp1, which I know they are there and not null as
tested
> > from subApp1 ServletContext. The whole code is:
> >
> > (MyPlugIn) myPlugIn = (MyPlugIn)
> >
((getServlet().getServletContext()).getContext("/subApp1")).getAttribute(myP
> > lugIn);
> >
> > This line of code gives null value from both mainApp and subApp1
> > ServletContext. I did explicitly set appropriate docBase and
> > crossContext="true" for both mainApp and subApp1 in tomcat4 server.xml
> >
>
> This sounds like an issue that should be reported against Tomcat.
>
> > The questions are:
> > 1) How do I get global variables across web applications within 1
> > virtual host and across virtual hosts using Tomcat 4 container?
> > 2) Is there a better method for sharing global variables across web
> > applications within the same virtual host, and across virtual hosts in
the
> > same server?
>
> One option is to put the relevant classes in Tomcat's common/lib
> directory, and make the appropriate information available through some
> static method (such as a factory pattern). Such statics are shared across
> all virtual hosts and all webapps in a single Tomcat instance.
>
> > 3) What is the best approach to scale from the above scenario to
> > distributed environment?
>
> Store the shared stuff in a database, EJB, LDAP server, or some other
> external resource.
>
> > 4) If Ldap is used for global variable distributed environment, what
is
> > the best design for mostly read and few updates of JavaBeans to Ldap,
both
> > for performance and security.
> >
>
> Most LDAP servers are optimized for read performance already. If that's
> not fast enough, consider caching the retrieved information in servlet
> context attributes in each webapp -- keeping in mind that you will need
> some technique to ensure that updates get propogated in a timely manner.
>
> > Any help is greatly appreciated. Thanks.
> >
>
> Craig
>
>
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