Re: Accessing files from within an application server

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 22 Feb 2008 08:57:39 -0500

Message-ID:

<opydnU46xt5JSSPanZ2dnUVZ_uevnZ2d@comcast.com>

Qu0ll wrote:

"Owen Jacobson" <angrybaldguy@gmail.com> wrote in message
news:8527acc0-c190-4ad4-bdf4-32531d0ce51b@s37g2000prg.googlegroups.com...

So what's going on? How do I reference files in WEB-INF/xml/*.xml from
within a servlet?

Include "WEB-INF/" in the name of the resource when locating it.
getResource and friends search from classloader roots, which in the
case of a webapp are:

- the webapp's own root (foo.war/)
- the webapp's classes directory (foo.war/WEB-INF/classes/)
- the root of each JAR file in the lib directory (foo.war/WEB-INF/
lib)

That's got it! Thanks muchly :-)

There are three resource-loader methods in a JEE app: Class#getResource()
<http://java.sun.com/javase/6/docs/api/java/lang/Class.html#getResource(java.lang.String)>

ClassLoader#getResource()
<http://java.sun.com/javase/6/docs/api/java/lang/ClassLoader.html#getResource(java.lang.String)>

and ServletContext#getResource()
<http://java.sun.com/javaee/5/docs/api/javax/servlet/ServletContext.html#getResource(java.lang.String)>

plus their getResourceAsStream() variants.

Each class's version of the method has slightly different rules about finding
the root of the provided 'path' depending on whether the argument begins with
a slash or not. For example, the ServletContext version takes a path that
"must begin with a "/" and is interpreted as relative to the current context
root." The others interpret paths relative to the classpath, not the same
thing, and do not require a leading slash. There are emergent consequences to
the way they do it that are not fully documented.

--
Lew