Iterating ArrayLists within HashMaps using JSTL

Question:

Iterating over a HashMap itself is straightforward using JSTL's tag. However, how do you iterate over the ArrayList values associated with each key in the HashMap?

Solution:

JSTL's tag provides flexibility in iterating over different data structures, including maps.

Iterating the Map:

This iterates over the map's entries, where each entry is a Map.Entry object with getKey() and getValue() methods.

Iterating the ArrayList:

To access the ArrayList associated with an entry, use entry.getValue(), which returns the list as an object. You can then iterate over the list as follows:

Combined Example:

    Key: ${entry.key}

    Values:

    
        ${item}
        ${!loop.last ? ', ' : ''}
    

This example iterates over the map, retrieving the ArrayList associated with each key. It then iterates over the ArrayList, displaying the key and values.

Additional Notes:

• The varStatus object provides additional information during the iteration, such as the current index.
• For a better understanding, refer to the provided Java translation of the JSTL code.