learn-co-curriculum / java-command-line-args-lab

Command-Line Arguments Lab

Learning Goals

• Practice passing arguments in via the command-line.

Instructions

Given the GroceryListDriver class again, modify the program to take in the file as a command-line argument instead of prompting the user for the file path.

Reuse the last lab to implement the read and write methods and then make sure that everything passes the unit tests again.

To implement the reading of command-line arguments, consider the following instructions and tips:

• Modify the GroceryListDriver class.
  • Replace the Scanner object that is prompting the user for the file path with getting the file path via the command-line.
  • Refer to the Command-Line Arguments lesson as needed.
• When running the GroceryListDriver class, pass in a file named grocery-list.txt.
• Make sure the unit tests all still pass successfully.

Example Output

Consider the example output if no file is passed in via the command-line:

Please specify one file path as a command-line argument.

Consider the example output if we do pass in the file as a command-line argument:

Apples
Bananas
Cookies

Stretch

Along with passing the file path into the program via the command-line, also pass it the contents of the grocery list. If we were to implement this and then execute the Java program via the command-line, the command would look like this:

java GroceryListDriver grocery-list.txt Apples Bananas Cookies