Whats the best way to specify a path to read from class-path even if project was a jar

Question

I am trying to read a Properties file in a maven nature project using the Properties.load(); I am specifying a path as a string ex. "./someFolder/file.properties", but when I try to use my project as dependency in other projects I am forced to copy those files to the other project , simply because the "." means current directory. Is there a way to specify a path so it will always be valid despite where I am calling it from ? , I have tried using the MyClass.class.getClassLoader().getResourceAsStream() but I am having trouble using it , it worked sometimes and failed other times.

Answer 1

There are lots of misconceptions in your question.

"." means classPath

No. When used inside a filesystem path (i.e. a path passed to the constructor of a File, or FileReader, or FileInputStream), "." means the current directory.

When used in a resource path (i.e. passed to Class[Loader].getResource[AsStream]()), it's invalid.

The trick is to carefully read the documentation.

getResourceAsStream() expects a /-separated path.

When using ClassLoader.getResource[AsStream](), this path always starts from the root of the classpath. So you would pass a path looking exactly like a fully qualified class name, except the dots would be replaced by slashes. So, com/foo/bar.properties looks for a resource named bar.properties, in the package com.foo.

When using SomeClass.class.getResource[AsStream](), either the path starts with a /, and the path starts from the root of the classpath, or it doesn't, and it starts from the package of SomeClass. So, if SomeClass is in the package com.foo, using /com/foo/bar.properties is equivalent to using bar.properties.

It's hard to tell what you're doing wrong, since you're not providing any detail. But you really need to understand the difference between opening a file on the file system, and reading a resource loaded by the class loader. Sometimes, the resources just happen to be loaded by the class loader from the filesystem, because the classpath happens to contain directories, and not just jar files.

Answer 2

I noticed that my problem was that I had my properties files in the project path itself, and that the ClassLoader.getResource[AsStream](); looks is the target/classes folder, and that I didn't have the resources folder in my project.

I solved it my adding the resources folder to my build path and adding my files in the src/main/resources as the following src/main/resources/foo/bar.properties and loading it by SomeClass.class.getClassLoader().loadResourceAsStream("foo/bar.properties");.