How do I get a resource using Class, ClassLoader, and URL

Question

I am writing a simple JSF application and am trying to get a resource (database.properties file) using Class, ClassLoader, and URL that is not working. url is null and I don't know why. I have done a lot of research but without success.

Code:

Class cls = Class.forName("<packagename>.SimpleDataSource");
ClassLoader cLoader = cls.getClassLoader();
URL url = cLoader.getResource(fileName); // fileName = "database.properties"  w/o the double quote
FileInputStream in = new FileInputStream(url.getFile());

http://balusc.blogspot.in/2008/07/dao-tutorial-data-layer.html Scroll down to the section `Properties file loader`. — Sandeep Chatterjee, Mar 17 '14 at 05:11

score 0 · Answer 1 · answered Mar 18 '14 at 19:20

Thanks for your comment Sandeep, it was helpful. I found out that my properties file was in the wrong place. I then moved it inside my src folder under the java resources folder and now my properties file gets loaded in. I have a new problem now but will start a new thread if I can't figure it out.

score 0 · Answer 2 · answered Mar 18 '14 at 19:51

Once you have a URL you can get an InputStream from it using url.openStream(), or you can simply use cLoader.getResourceAsStream(...) in the first place. Your current approach of

FileInputStream in = new FileInputStream(url.getFile());

will work on some platforms but not all, and only when your application is running from a directory on disk. It will fail if your classes and resources are packed up into a JAR, but if you use getResourceAsStream it will work from a JAR as well as an unpacked directory.

How do I get a resource using Class, ClassLoader, and URL

Code:

2 Answers2