Regarding the classloader: The read and save methods, respectively, reside
in two different classes. The read method is static and called like
ReadClass.GetProperties (i.e. without an object). The save method is part
of a servlet class and is not static. May this cause problems?
I know practically nothing about classloaders et al, and I do not tamper
with them anywhere else in the web app.
Jan Andersson
Senior Software Engineering Specialist
IBM Rational Brand Services
+46 (0)70-793 23 02
Oddegatan 5
164 92 Stockholm
ALEX HYDE <[EMAIL PROTECTED]>
2005-11-14 16:46
To
Jan Andersson/Sweden/[EMAIL PROTECTED]
cc
Subject
Re: How to read and save a simple file?!?
Hi Jan,
This is one of things that's given me a headache in
the past. Take what I say with a pinch of salt as I'm
no expert. I would guess that (if your file is not at
the root of the class path) you might need to specify
a full path to the file relative to the root of the
classpath. I'm afraid this is just a guess.
For example if your properties file was located:
mydir/ReqProFPHubNotifier.properties
then you might need to try referencing it like:
cl.getResource("mydir/ReqProFPHubNotifier.properties")
or (absolutely)
cl.getResource("/mydir/ReqProFPHubNotifier.properties")
I'm afraid I'm guessing. I think I fudged this once
just through trial and error.
Good luck
ps: you are referencing the class loader via different
classes in each case so I'm not sure if this might
have an effect.
--- Jan Andersson <[EMAIL PROTECTED]> wrote:
> Hi all!
>
> This is a simple question, which should have a
> simple answer.
>
> I have a servlet in my webapp that reads a file with
> properties and
> displays them. You can change the properties and
> then hit "Save", which
> makes the servlet write the properties to a file.
> The problem I'm
> experincing is that when saving the properties, the
> file is not found.
>
> The code for writing goes like this.
>
> ClassLoader cl =
> ReqProPropConfig.class.getClassLoader();
> URL propsURL =
> cl.getResource("ReqProFPHubNotifier.properties");
> FileOutputStream out = new
> FileOutputStream(propsURL.getPath());
> PrintStream printOut = new
> PrintStream(out);
>
> and then a series of printOut.println writes the
> properties, one at a
> time, to the file.
>
> And the code for reading:
> ClassLoader cl =
> ReqProInitializer.class.getClassLoader();
> Properties properties = new
> Properties();
> String path =
>
cl.getResource("ReqProFPHubNotifier.properties").getPath();
> String decodedPath =
> URLDecoder.decode(path);
> InputStream in2 = new
> FileInputStream(decodedPath);
> properties.load(in2);
> in2.close();
> return properties;
>
> I use the classloader to be able to find the file
> without having to point
> out exactly where it is. (As I've been told, the
> classloader uses the
> classpath to find the file.) The code as it stands
> today (e.g. the use of
> URLDecoder) is mainly a result of trial-and-error.
> That is, it used to
> work but not anymore (which probably is due to
> testing in the real
> production environment, which isn't exactly what I
> used when I tested it.)
>
> If there's another way to read and write a file with
> properties
> (relocationability of the property file preserved,
> relative path ok) I'm
> VERY interested to hear.
>
> As you understand, I'm pretty new to both to Java
> and Tomcat, although I
> have some ten years experience of professional
> programming. So this
> questions in its simplicity is really annoying me.
> One doesn't think of
> reading and saving a simple text file as something
> that should be
> complicated.
>
> Please help!
>
> Jan Andersson
> Senior Software Engineering Specialist
> IBM Rational Brand Services
> +46 (0)70-793 23 02
> Oddegatan 5
> 164 92 Stockholm
>
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