You can then loop them and everywhere Item[x][y] != null, you display that item.
For the Item structure, I'd work with a system like this: Have one base Item class with the basics that every Item has; If every item has the same, leave it this way. If some Items are different (for instance, Health items, Weapon Items ...) inherit from the Item base class and use the factory design pattern. This allows you to 'load' your items from a database or XML. Don't create a class for every Item, as it makes your code to 'implementation-wise' and adding Items will be more difficult.
The following UML can make things clear: make the following. Then create some class that will spawn the items (factory pattern) and add them to the inventory.
Of course, the array idea only works with everything of size 1. Otherwise you could use some system that has a 'size' field in the Item class and prevent from inserting new items to zones which are taken