Pete Willemsen wrote:
>
I will also embed a few comments and responses below.
> Thanks for your response Craig. My comments are embedded in our discussion.
>
> At 04:21 PM 4/24/99 +0000, you wrote:
> >Pete Willemsen wrote:
> >
> >> Hello.
> >>
> >> I'm attempting to use
> >>
> >> System.getProperty("user.dir")
> >>
> >> in my servlet to locate the a directory that is hopefully the directory
> >> where my servlets were installed. I need to write some persistent database
> >> files as the servlet runs.
> >>
> >> Here's where I'm getting confused... On other servlet engines such as JRun
> >> this system call returns the directory where the servlets themselves were
> >> installed. However, on my Apache JServ (on a Linux system) setup, this
> >> system call returns "/".
> >>
> >> I guess this seems strange to me and I'm not sure where I messed up (or if
> >> I did). If my servlet is used at a site where I don't have root access, I
> >> will not be able to use it since (obviously), I probably won't be able to
> >> write the files requried by my servlet to maintain persistence.
> >>
> >> So, a few questions that I have are
> >>
> >> 1) Is getProperty("user.dir") returning what is considered to be correct
> >> information (especially in JServ)?
> >>
> >
> >The value of the "user.dir" property is set by the JVM, not the servlet
> >engine. It is the current working directory of the operating system process
> >that is running the servlet engine, which may or may not have anything at all
> >to do with where servlets are loaded from.
> >
>
> The current working directory of the operating system is then "/" (or the
> root directory according to what I've experienced.
>
> If "user.dir" is set by the JVM, do you know if other JVMs that run on
> Linux set user.dir to someplace else? I'm using the blackdown.org port of
> jdk1.2.
>
The "user.dir" property is the current working directory for the JVM that is
running the servlet engine. Java code has absolutely no opportunity to modify
this. This implies that your ISP has either explicitly decided to start the JVM
with a current working directory of "/", or that this is the default for JServ in
automatic mode.
It turns out that the latter is the default when Apache JServ is started in
automatic mode ... at least on my Linux box, and apparently also on your ISP.
This is all based on the servlet engine you are running and how it is configured.
>
> >>
> >> 1.a) Why is there inconsistency between servlet implementations?
> >>
> >
> >There is inconsistency because there is nothing in the servlet API spec
> >requiring there to be consistency. The place you load a servlet from usually
> >has nothing to do with the current working directory of the servlet engine.
> >There is always some mechanism to specify the "class path" for the
> servlets to
> >be loaded from. In the case of Apache JServ, you do this with the
> >"repositories" configuration parameter of the zone properties file. You can
> >list as many directories and ZIP/JAR files as you like.
> >
> >By the way, you can change where Apache JServ is started if you start it in
> >"manual" mode instead of "automatic" mode. Then, the current working
> >directory will be wherever your startup script makes it.
> >
>
> This, unfortunately, will not work for me as my ISP starts the servlet
> engine in automatic mode and I have no say in this decision, especially
> when I'm one of many people who will potentially use servlets.
>
The initialization parameter approach is still useful ... worst case, but still
feasible, of course, is hard coding the pathnames into your servlet.
>
> >>
> >> 2) What are other ways to get the path to the directory where the servlet
> >> exists?
> >>
> >
> >Why do you insist on storing your data in the same directory that the
> servlets
> >are loaded from? What would your software do if you packaged up your
> servlets
> >in a JAR file, instead of a directory?
> >
> >The typical approach to this type of problem is to define an initialization
> >parameter for your servlet, used to pass in the pathname of the directory in
> >which data files can be found. In your zone properties file, you might say:
> >
>
> I understand your solution, but unfortunately, I'm in a situation where I
> do not have control over my zone. My ISP has setup a directory in my
> account where I can place servlets, just as if I was writing Perl CGI scripts.
> I would like that directory be the place where I write my log files,
> database files, etc... If I was writing Perl scripts, writing to a
> relative file name (without path info) would write a file to the same
> directory the Perl script is installed at.
>
> How do most ISPs handle servlets? I can't imagine that they allow their
> users/clients access to the setup files (jserv.properties, and maybe even
> the zone properties set up for each user/client).
>
> I guess the fact that Java Web Server and JRun (run on an NT machine, so
> maybe the JVM is setting things differently there) return the directory
> where the servlets were installed when one queries "user.dir" make me think
> that this method isn't so portable after all.
>
> So, the big question to me is what does a user/web-creator do when they
> want to use servlets and keep logfiles, but do not have the ability (based
> on ISP constraints) to (1) start JServ in manual mode and (2) change the
> init parameters in the zone properties file?
>
They switch ISPs. If the ISP won't even set you an initialization parameter,
they are not worthy of your business.
Craig McClanahan
----------------------------------------------------------------
To subscribe: [EMAIL PROTECTED]
To unsubscribe: [EMAIL PROTECTED]
READ THE FAQ!!!! <http://java.apache.org/faq/>
Archives and Other: <http://java.apache.org/main/mail.html/>
Problems?: [EMAIL PROTECTED]
