如何在运行Java应用程序时使用classloader将目录指定为classpath以读取其中的文件？

Question

Let's say there is a file abc.txt present in directory dir . I am trying to run a java application using following command java -cp dir;myjar.jar com.example.Main

And in Main class, I am trying to access this file like this getClass().getResource("/abc.txt") . But this is returning null. I am not sure what's wrong here. Any pointers will be appreciated.

Answer 1

Since the file is in the root of the classpath directory, you need to use "/abc.txt" , otherwise it's looking in the package folder for the class in question.

Just like the javadoc of getResource says:

Before delegation, an absolute resource name is constructed from the given resource name using this algorithm:

• If the name begins with a '/' ( '\/' ), then the absolute name of the resource is the portion of the name following the '/' .

• Otherwise, the absolute name is of the following form:

   modified_package_name/name 

  Where the modified_package_name is the package name of this object with '/' substituted for '.' ( '\.' ).