How to find out of path of an application

[Vernon Wu <ve...@gatewaytech.com>]

In my current project, the user can upload his/her photos to the web server so that people can view these photos. I 
create an image directory under webapps/myapp. When the user upload his/her photos at the first time, a new 
directory under the image directory is created with the user' user ID. 

In a Struts-like structure, req.getContextPath() + "/images" doesn't field a right path, but "myapp/images" in a Java 
bean. How can I find the right path?

Thanks for your help.

Vernon




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Re: How to find out of path of an application

["Craig R. McClanahan" <cr...@apache.org>]

On Fri, 19 Jul 2002, Vernon Wu wrote:

> Date: Fri, 19 Jul 2002 17:26:46 -0700
> From: Vernon Wu <ve...@gatewaytech.com>
> Reply-To: Tomcat Users List <to...@jakarta.apache.org>,
>      vernonw@gatewaytech.com
> To: tomcat-user@jakarta.apache.org
> Subject: Re: How to find out of path of an application
>
> Since no one would like help me out, or it is too simple question, I
> have to hacked out a soluation myself.
>

Your approach only works under the following conditions:

* Tomcat sets its working directory to CATALINA_HOME (depends
  on how you start it)

* Webapp is deployed in the "webapps" subdirectory (not required)

The canonical approach to this is documented in the Javadocs for
ServletContext:

  String saveDirectoryPathname =
    getServletContext().getRealPath("/images");

However, the problem with this approach -- which has been discussed at
least three times in the last week on this mailing list (see the
archives), and untold numbers of times before -- is that you are *not*
guaranteed that there is such a thing as a "directory" that corresponds to
your webapp.  It is perfectly legal for a servlet container to run a
webapp directly from a WAR file, or store it in some other internal format
that does not correspond to a filesystem.  In such cases, getRealPath()
will return null.

A far safer thing is to pass the pathname of a directory to store images
into as a servlet initialization parameter, or something like that.

Craig


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Re: How to find out of path of an application

[Vernon Wu <ve...@gatewaytech.com>]

Since no one would like help me out, or it is too simple question, I have to  hacked out a soluation myself.

Here is what I find after more than a halp of hacking:

		String saveDirectory = "webapps/" + req.getContextPath() + "/ images";
		File f = new File(saveDirectory);

	f.isDirectory() - No, f.exists() - No, f.canWrite() - No
But,
		String saveDirectory = "webapps/" + req.getContextPath() + "/ images";
		File f = new File(saveDirectory);
		f = new File(f.getAbsolutePath());

	f.isDirectory() - Yes, f.exists() - Yes, f.canWrite() - Yes

That doesn't sound right, does it? Why I need to get absolute path to be able  write a file?

7/19/2002 10:40:48 AM, Vernon Wu <ve...@gatewaytech.com> wrote:

>
>In my current project, the user can upload his/her photos to the web server so that people can view these photos. I 
>create an image directory under webapps/myapp. When the user upload his/her photos at the first time, a new 
>directory under the image directory is created with the user' user ID. 
>
>In a Struts-like structure, req.getContextPath() + "/images" doesn't field a right path, but "myapp/images" in a Java 
>bean. How can I find the right path?
>
>Thanks for your help.
>
>Vernon
>
>




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