1.3-Object-Georienteerd-Programmeren

Reading the file system

As an IT professional, you will be dealing with the file system on a regular basis, whether it is to create files,remove files, read from files, etc.

In this assignment we are going to write a script that explores a folder and all its subfolders of your operating system.

For this we are going to use the java.io.Fileclass which can be found in the standard library of Java. Because you (from this moment on) need to use classes that you don’t know about yet and you thus should get familiar with reading official documentation, we’re not going to explain too much about this class, but redirect you to the official documentation of this class instead.

Therefore, study the following page carefully: Java File documentation

Please note: With this command we are going to use the file system and so you have to be a bit careful with what you actually instruct Java to do with your file system. It is possible to actually “break” something if you invoke a method without understanding what it does. We will however today focus on reading only, so you should be fine!

Collect all file names in folders

There are several ways to access files and folders. We have provided a sample folder with some files that you can download here. This sample folder contains:

• samplefolder
  • subfolder1
    • style.css
    • website.html
  • subfolder2
    • LostFile.java
  • description.txt
  • elephant.png
  • giraffe.png
  • README.md

Now in the Application class you must implement the method listAllFiles(String directory). We are going to focus on the files in the root directory and the names of the subdirectories. You don’t have to worry about the contents of the subdirectories. (You are obviously allowed to show these as well, but it will make your solution a bit more complex!)

The idea is to open the root folder and list the names of all the subfolders and the files in that folder. We will first show all subfolders before showing all the files. Of the files you can print out the file size in bytes. You have to figure out which method you can use to get the length of each individual file.

Your result will look like this:

Directories:
- subfolder1
- subfolder2

Files:
- description.txt (63 bytes)
- document.csv (120 bytes)
- elephant.png (14426 bytes)
- giraffe.png (11633 bytes)
- README.md (344 bytes)

Make sure to implement error handling, so that if you provide a non-existing directory your program terminates.